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Total electrical failure


Paul64
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Just got back from the UK. Had a problem with my LR :( Total loss of electrics on two separate occasions after driving through rain storms. It only happens after stopping the engine. Nothing works, no ignition lights, refuses to start etc. Then after about 10 mins fires up. Checked and cleaned up earths to gearbox and bulkhead, but all looked pretty clean already. Not sure if it is water getting in somewhere? My cousin reckons it may be my alarm immobiliser, but this has never been a problem before. However, he may have a point as I have 2 batteries (Split charged) wired up to separate things, but all goes off when problem kicks in.

Any ideas would be appreciated?

Cheers, Paul

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It may help if you let people on here know the age and what kind of land rover you have as the problem that you have, may have happened to someone else-any if not all info would be ness to even try to diagnose the problem with a possible of solution for it

HTH

John

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For jbs, IIRC we are talking a 300TDi Defender, but with plenty of additional bits and pieces.

Paul is the man behind http://www.transylvania4x4tours.com/

"Just back from the UK" probably means he has just driven to Transylvania :-)

Mainly I think I'm just tossing ideas into the pool here.

Is the immobiliser designed to cut the power to everything powered from BOTH batteries?

If it is, then false triggering of the immobiliser could be the cause.

If the immobiliser is designed to just prevent the engine starting and running, by cutting the feeds to the starter and fuel solenoid, then I don't see the immobiliser can be blamed if you are losing power to other circuits as well.

In general terms, running until the engine is switched off, then all dying, points to the alternator supporting everything while the engine is running, but the battery not being effective when the engine stops. I've had this happen when the Earth to the battery became disconnected, but the voltage tends to rise under these circumstances. In my case the failure was mechanical, so there was no 'OK in 10 minutes' result, it was broken until the fault was repaired.

Combining those two, if the immobiliser is configured to disconnect the earth from both batteries, look at the power circuit to the immobiliser, both the positive 12 volts AND the earth return.

Water, as in rain storms or water spray, doesn't affect 'normal' 12 volt stuff, like starters and filament bulbs, but can affect 12 volt electronics.

You have associated the failures with the rain storms, therefore water spray, so think about where any electronic control units are.

If the failure is due to water spray, I suspect the 'self repair' may be down to heat soak drying out 'whatever' is being affected by water.

If the association with water spray is incorrect, is the 'driving through rain storms' causing additional work that gets something else heated (you know the vehicle best)? In this case the self repair is due to 'whatever' cooling down, rather than being warmed and dried by heat soak.

As I say, Ideas or Points to consider.

Regards.

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Thanks David, there is a lot in your reply to get me started. The only other item I noted when driving through rain was slight flickering of the headlamps which was also noted on the headlamp dash light. Not sure whether this is coincidental with the actual problem or associated.

The alarm immobiliser is a cobra system, but I only have the guarantee rather than the workbook, so not sure if they are still building these systems since mine was fitted in 1994. I will try and contact them regarding the actual mechanism of the immobilisation.

When I was cleaning both battery negative earths, I noticed both cables were joined and were fitted to the gearbox at the same point.

I have been having other electrical gremlins as you which I'm not sure will help with this thread or just muddy the water:( The windscreen wipers activate the first time I switch the headlamps on and every time when flashing with high beam.

Both batts are fully charged, but the alternator is suspect as the volts drop when engine revved.

One muddy picture hey :)

Cheers, Paul

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I had a similar thing on my 90. i might have electrics but then everything would go off and nothing...... i found it to be the power cables to the battery, the cables themselves where getting tired and starting to split and the wire breaking. chopped them back a couple of inches and put new ends on and all perfect again.

its one option. :)

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Snip

I have been having other electrical gremlins as you which I'm not sure will help with this thread or just muddy the water:( The windscreen wipers activate the first time I switch the headlamps on and every time when flashing with high beam.

One muddy picture hey :)

Cheers, Paul

I always enjoy your posts Paul, it's just so much fun providing support from several thousand miles away to an owner more expert in biological circuits than electrical circuits :-)

I'm not a Defender type person, but I suspect both the headlight dip control and the wipers are on column stalks, possibly the same stalk.

Assuming both are on the column somewhere, I think you should look for damaged insulation in the wiring loom between the connection to the loom in the dashboard and the actual controls. I wouldn't be surprised to find the insulation has been chaffing as the column is turned. But the damage is just as likely to be caused by the point of a self tapping screw, or similar sharp edge.

Your fire extinguisher is within date I hope?

Do Britpart list replacement Lucas smoke, for when the original escapes?

Good Luck!!

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Your fire extinguisher is within date I hope?

Do Britpart list replacement Lucas smoke, for when the original escapes?

Good Luck!!

LOL - I used to keep the fire extinguisher under my seat, but now have it to hand in the cabin :)

The headlamp on and off unit on the steering is separate to the flasher lever. I changed the on off unit last moth as the headlamps used to turn themselves off, which was a little frightening at night! Thankfully the new unit resolved that problem.

My cousin had the dash off last year and removed 20 metres of unused cables from old projects! He inspected every cm of cable that he could get to and managed to eradicate the wiper activation when turning lights on for a few months, although we never knew how.

DSC07402600x450.jpg

DSC07411600x450-1.jpg

You will see from company website, business is on hold for a while whilst I work on a contract in Germany, so only a few hundred miles away at the moment :)

Thanks for your help as always David

I had a similar thing on my 90. i might have electrics but then everything would go off and nothing...... i found it to be the power cables to the battery, the cables themselves where getting tired and starting to split and the wire breaking. chopped them back a couple of inches and put new ends on and all perfect again.

its one option. :)

Thanks for the tip although my power cables look OK :)

Cheers, Paul.

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Mainly I think I'm just tossing ideas into the pool here.

Is the immobiliser designed to cut the power to everything powered from BOTH batteries?

If it is, then false triggering of the immobiliser could be the cause.

If the immobiliser is designed to just prevent the engine starting and running, by cutting the feeds to the starter and fuel solenoid, then I don't see the immobiliser can be blamed if you are losing power to other circuits as well.

IIRC the winch, ARB's and power inverter are connected directly to one of the batteries and i think but not 100% sure the CB is too.

everything else is connected to the defender original wiring loom, connected to the other battery.

if it happens again it maybe worth checking these other things to make sure they work to rule out the batteries, also keep the multimeter close and check voltage of both batteries next time very very long shot but if its down to lack of voltage you may have one dead battery once stopped then the 10min allows the battery to save enough power to bridge the split charge allowing starting off the good battery(i know i know very long shot but may be :D) also split charge is x-eng so doubt any poblems there.

the only damaged wires that we found were the ones going to the wiper motor, these were re-insulated all other wiring that i could get to was fine, including IIRC engine bay.

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IIRC the winch, ARB's and power inverter are connected directly to one of the batteries and i think but not 100% sure the CB is too.

everything else is connected to the defender original wiring loom, connected to the other battery.

if it happens again it maybe worth checking these other things to make sure they work to rule out the batteries, also keep the multimeter close and check voltage of both batteries next time very very long shot but if its down to lack of voltage you may have one dead battery once stopped then the 10min allows the battery to save enough power to bridge the split charge allowing starting off the good battery(i know i know very long shot but may be :D) also split charge is x-eng so doubt any poblems there.

the only damaged wires that we found were the ones going to the wiper motor, these were re-insulated all other wiring that i could get to was fine, including IIRC engine bay.

Thanks Dave. I checked both batts with multimeter as soon as electrics were lost. 12.3V in one and 12.6V in the other. This ones a mystery!

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Voltages look ok, I suspect an issue with the heavy current cables as suggested above. If your inverter etc is connected directed to the second battery, then the immobiliser can't be in the mix. I'd suggest internal deterioration of one of the cables, probably the earth if it affects both batteries - maybe water creeping up inside the insulation?

You could check it by running a jump lead from the neg terminal of the starter battery to the BODY (not the positive stud!!) of the starter motor. If the jump lead is suddenly effective then the OE leads aren't.

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Reminded by the comment from Turbocharger, I recalled this statement from post #4 "When I was cleaning both battery negative earths, I noticed both cables were joined and were fitted to the gearbox at the same point."

If that means 'two cables joined together, then a single cable to the gearbox', then I'm a bit uneasy about that. Without getting too technical about a situation we can never prove one way or the other, my instinct says I'd rather see two separate cables going all the way from the battery terminals to the gearbox. I'll allow use of the same attachment bolt at the gearbox, but I'm not happy with the joint in the middle, whether it's in 'mid-air' or two cables combined at a bodyshell connection point.

Cheers.

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Voltages look ok, I suspect an issue with the heavy current cables as suggested above. If your inverter etc is connected directed to the second battery, then the immobiliser can't be in the mix. I'd suggest internal deterioration of one of the cables, probably the earth if it affects both batteries - maybe water creeping up inside the insulation?

You could check it by running a jump lead from the neg terminal of the starter battery to the BODY (not the positive stud!!) of the starter motor. If the jump lead is suddenly effective then the OE leads aren't.

Thanks - I noticed that only the starter battery neg strap is insulated. The second battery has a braided like negative strap without insulation, is that bad?

David - both these negative earthing straps are only connected at terminal ends by the bolt that connects them to the gearbox :)

Cheers, Paul

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Thanks - I noticed that only the starter battery neg strap is insulated. The second battery has a braided like negative strap without insulation, is that bad?

David - both these negative earthing straps are only connected at terminal ends by the bolt that connects them to the gearbox :)

Cheers, Paul

OK, Ignore that overnight thought about mid-span joints then!

Braided and uninsulated earth straps were the common way of doing things, so nothing intrinsically wrong there.

I'd wonder about it's current carrying capacity if that battery is supplying your winch, but we aren't chasing winch performance here, so possibly replacing it with a cable as thick as the one that goes to the starter is something for the back burner.

Cheers.

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OK, Ignore that overnight thought about mid-span joints then!

Braided and uninsulated earth straps were the common way of doing things, so nothing intrinsically wrong there.

I'd wonder about it's current carrying capacity if that battery is supplying your winch, but we aren't chasing winch performance here, so possibly replacing it with a cable as thick as the one that goes to the starter is something for the back burner.

Cheers.

Thanks David - just had a quick look at that braided strap and note that there is a section in the middle that is a frayed with some unbinding. It is intact, but looks a little rough where it bends down to meet the gearbox. Do you think if water was being thrown up from the ground and soaking this area of damage, that this would be enough to cause problems?

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Thanks David - just had a quick look at that braided strap and note that there is a section in the middle that is a frayed with some unbinding. It is intact, but looks a little rough where it bends down to meet the gearbox. Do you think if water was being thrown up from the ground and soaking this area of damage, that this would be enough to cause problems?

My initial instinct is to say No, in-line with my previous comment that water doesn't affect a simple 12 volt circuit. I once had to prove this to sceptics by setting a 12 volt motor running, and then immersing it totally in a container of water, where it continued running quite happily. After that they would accept rapidly cleaning and cooling 12 volt motors by washing then in clean cold water (then putting them back into use, when they rapidly dried).

However ....

I am reminded of the repeated cases of the engine earth strap on the petrol V8 engine in the 38A.

This is a standard cable, with lugs crimped on both ends. Bolted low down on the engine it gets covered in any oil leaking from the rocker covers, together with dirt and water from road spray. Add in the vibration from the engine, together with the heat cycling from the engine warming and cooling, and the relatively stiff cable strands start to work loose inside the crimp, allowing corrosion to take place.

The first sign of this joint failure was a potential difference between the engine (alternator) earth and the battery earth fed to the instruments in the car. As the engine sensors (particularly the coolant temperature sensor) used the engine earth as a reference value, this potential difference between the sensor earth and the instrument earth caused the instrument to misread.

If this joint failure was ignored, and became worse, the next effect was ineffective charging of the battery as the negative part of the alternator to battery charging circuit became even higher resistance (with even greater volt drop).

So, while water itself won't cause a problem, I wonder if it's presence as a lubricant may exacerbate some other problem. This is not something that can be judged from afar. If, in your situation, the damage is only the loss of up to 50% of the strands, I don't see it causing your current total failure problem.

Look closely at both where the braid is terminated into the lug on the end, and the frayed section, give them both a good tug. If these seem mechanically secure then it's probably as much as you can do, apart from the parallel connection, Under Fault Conditions, of the braid via another cable, as advised by TC.

Note also the potential problem of replacing a very flexible braid with a much stiffer cable. The flexible braid will be much better at absorbing the vibration that damages the stiffer cable. In these circumstances the use of welding cable, with it's many fine strands, has an attraction over the use of the traditional starter motor cable.

No clear cut answer there, but even after considering the possibilities, I'd still conclude that if you cannot mechanically break the connection with a hand pull, the state of the braided cable is not the cause of your total failure problem, ESPECIALLY as it only affects the 'ancillary' battery, not the main 'engine' battery.

Moving on

If you find nothing wrong, and have to travel back to Germany with the problem 'not fixed', consider making a temporary mount for your multimeter on the dashboard, and monitoring the voltage. I won't be prescriptive about what actual value you should see, as it will vary depending on where the meter is connected to, and what electrical loads you have switched on. What I'd be looking for is a stable voltage under whatever stable conditions exist at the time.

Remember that the standard 'two places of decimals' reading is showing Hundredths of a volt, which is really too fine for what we need, so don't be mislead by the fourth digit changing every 2 seconds.

A decent internal battery will keep the meter powered for hours, but carry a spare if you have one.

Cheers.

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is it not worth trying the alarm/immobiliser set up?

go to a place far away from people

sit in vehicle

arm alarm

wait, usually 10 secs, then set it off, make sure no keys etc are in the ignition until its going off.

and before disarming it try to start it

if you have no dash lights thats telling us its wired in to the ignition and could be the source of the problem, if you get dash lights its time too look else were.

another fault could be the ignition barrel on its way out maybe, only guessing here as not sure what they go like when there going out.

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Thanks David and David for all the info.

I went for a 20km run this am along an autobahn. I connected the 2nd ancillary battery to the multimeter. It started off idling at 13.22V, then I started driving at a steady 65mph for 20kms. The voltage gradually went down slowly to 12.63V. I then pulled off the autobahn into a lay-by. I left the engine running for five minutes but when idling once more the volts did not pick up at all. I then turned the engine off and the volts slowly reduced to 12.45V, then all the power cut out as before. When I tried to start the engine there was a slight clicking in the starter motor, but not enough to turn the engine, and then all the remaining power quickly drained away to nothing. After 5 minutes the power came back, I started the engine and the idling reading returned to 13.2V.

I then stopped the engine once more, took the keys out and armed the alarm system. After 15 seconds with me sitting in the car the alarm sounded. I then put the keys quickly into the ignition but the vehicle was immobilised. However, the lights did illuminate on the dashboard when I tried to start the engine with the alarm sounding.

Does any of that give you any clues as to what is going on?

Cheers, Paul

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SNIP

Does any of that give you any clues as to what is going on?

Cheers, Paul

No. (Dammit!)

But on the positive side, we can now see 'A' problem.

I'd like to see the results of monitoring the vehicle battery rather than the auxiliary battery.

Jumping ahead, IF the voltage on the vehicle battery is also reducing while in use that is a problem we have to cure.

Jumping ahead two steps I think .... no, better to do one step at a time, even though it appears a painfully slow process.

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Thanks - just been for another drive, this time a short 5km blast.

I should have mentioned that this mornings autobahn run was in the rain. Also both batteries are identical and new, bought in January this year.

My last 5km short run was in the dry.

Engine off and not running for 4 hours.

Main battery 12.46V

Ancillary battery 12.67V

Engine on - tick over

Main battery 13.10V

Ancillary battery 13.10V

Then I left the multimeter attached to the main battery when went for drive. Same thing happened - Volts dropped slowly to 12.78 and did not pick up when stopped and on tick over. After 5 mins tick over I turned engine off. Voltage continued to drop over 5 more minutes whilst engine off to 12.70

I then turned engine back on and tick over voltage went up to 13.26V

Is the plot thickening or is this beginning to make sense?

At this point I left both batts connected and are x-eng split charged.

Cheers, Paul

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Personally, I'll say we are collecting data. I'm not able to jump directly to why the system voltage disappears completely, and then self heals. At the moment I'm inclined to head towards the fault condition we can see and more easily understand. Having the voltmeter connected while driving is very useful, and I'm glad you were able to set that up.

I don't see anything in the readings to indicate a problem with the split charging.

The voltage figures while the engine is running are low, and this points towards the alternator not performing correctly. I recall there has been a history of 'alternator problems' and you mentioned in post 4 that "the alternator is suspect as the volts drop when engine revved" I seem to think we failed to cure this before, and probably hoped it would go away, or at least that it wasn't significant.

It now occurs to me that you should check for AC out of the alternator. With the engine off, but everything still connected, just change the meter to read AC instead of DC. When the engine is running you might change the range switch down to 2 Volts or lower to get some meaningful readings. The value may increase as the current load on the alternator increases. Ideally, we don't want to see any AC value. IE, the readings should be zero.

I don't suppose you have any means of displaying the current being supplied by the alternator?

If you are travelling back to Germany soon, I suggest packing your spare alternators, on the basis that it will be easier to find a specialist in Germany than at home. I may be wrong, but my recollection is that no-one can be 100% certain about the health of even your standby alternator, so it will be good to have your alternators tested under load.

Cheers.

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Thanks David,

I have just been out again. this time with the 2nd batt disconnected.

Engine off - 12.37V Engine idle 13.25 during run volts went down to 12.79V. The difference this time was that when I stopped the volts returned on idle to higher than before run. However, the reading was jumping about between 13.45V and 13.7V.

How do I check the alternator? Where do I place the probes?

Cheers, Paul

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How do I check the alternator? Where do I place the probes?

Cheers, Paul

For the initial AC check the probes can be on the battery, where you have them now, just change the switches on the meter.

If the AC check gives zero volts it 'proves' the diode (rectifier) pack in the alternator is OK.

You will see the next tests require connections directly to the alternator, so you could set up those connections now, and do the AC tests from them. I don't think it will make any difference to the results, so do whichever is most convenient.

The next test would be of the alternator installation, to establish the difference between the DC voltage at the alternator and the DC voltage at the battery.

For this I'd ask you to connect one lead of the meter to the CASE of the alternator, and the other meter lead to the NEGATIVE terminal of the vehicle battery.

Note the reading at idle and while driving, also ensure there is a good electrical load switched on (like all the lights plus the heated rear window). I'd want this reading to be always less than one volt DC.

Then I'd ask you to disconnect BOTH meter leads, then connect one meter lead to the POSITIVE of the vehicle battery, with the other meter lead to the OUTPUT terminal of the alternator. You must take care when making these connections that neither end can slip and hit bare metal (earth) while still connected to the battery positive or the alternator output terminal.

Again, Note the reading at idle and while driving, also ensure there is a good electrical load switched on (like all the lights plus the heated rear window). I'd want this reading to be always less than one volt DC.

However, the reading was jumping about between 13.45V and 13.7V.

This jumping is interesting. It indicates EITHER a loose connection, OR something switching in and out, altering the current draw on the alternator. Listen for clicking, or the engine speed / note changing as the alternator is loaded / unloaded.

My inclination is to say that a straightforward poor connection will not cause any noise change, but that load switching will. Of course, if the poor connection is in the operate circuit of a relay, which applies the additional load when it operates, then a noise change will occur. Nothing is really simple, all the data needs to be assessed together.

when I stopped the volts returned on idle to higher than before run.

That's good. It tempts me to suggest leaving the second battery disconnected for the time being.

Cheers.

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Thanks David,

I will have to wait until Wednesday before I can continue with the testing. I am in Germany, an hour ahead and its getting dark now. Thanks for all your help with this and it is great that a picture is forming. Can you recommend a way of fitting the probe to alternator output or casing whilst driving?

As a point of interest I did buy a new alternator last month as a back up. Do you think it is better to stick with the testing or just swap over to the new alternator?

Cheers, Paul

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Hi Paul,

I'd stick the new one on and get the other(s) checked out , before you do a quick test is to disconnect the main charge wire - thick brown one- with ign off everything switched off but vehicle battery connected , set your test meter to amps hold the red probe on the brown wire and the black one on the stud the wire was connected to . Any reading at all would indicate a faulty diode pack , which is also suggested from your results on the move ie lower volts at revs than at tickover.

Note that the heavy brown wire will be live so don't earth it ;)

hth

Steveb

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