Pastycrimper Posted June 20, 2011 Share Posted June 20, 2011 I was driving along yesterday listening to Test Match Special on LW and every now and then chronic radio interference occured (admitedly not that unusual on long wave). It wasn't until I had the radio off and was waiting at a junction that I noticed my headlights (and sidelights) were flashing on and off, along with the advosry light on the dash. Note the lights were switched off! At home I just sat in her parked on the drive still running with the lights off. Every now and then I'd hear a relay go crazy and the lights flashing on and off. It was defintely this which was ruining my radio pleasure! Anyone know what this is? Surely if the headlight stalk switch is off, the relay cannot be actuated!??? Looking at the wiring diagram I notice two relays a dim/dip relay that seems semi-isolated from the stalk switch........which I am guessing can be actuated regardless of the stalk switch position??? This has never happened before - the only things I have done recently are drive with a trailer attached - could a short/damage in the trailer hook up cause this? I also cleaned the engine but I made sure that the wiring was protected. Note that if I switche the headlights on using the stalk everything works fine as expected. Could do with sorting this as I keep freaking out drivers in front of me during the daytime who think I am obsessantly flashing them and then look to see a massive LR with Bullbars - probably think I'm a roadrage loony Thanks Ziggy Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 20, 2011 Share Posted June 20, 2011 Was it raining? Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 20, 2011 Author Share Posted June 20, 2011 Was it raining? It wasn't raining at the time but it has been very wet suddenly down here in Kernow....actually, thinking about it, at times it probably was raining/drizzling yes....... Quote Link to comment Share on other sites More sharing options...
western Posted June 20, 2011 Share Posted June 20, 2011 dim dip relay only operates when engine is running & sidelights are on, it goes off when you switch on normal dipped headlights & should not affect the normal dip/main beam stalk selection. you haven't said what year/model your truck is, there are 2 different dim dip systems 7 neither are legally required in the UK. the lighting reg for dim dip was recinded a few years ago. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 20, 2011 Author Share Posted June 20, 2011 dim dip relay only operates when engine is running & sidelights are on, it goes off when you switch on normal dipped headlights & should not affect the normal dip/main beam stalk selection. you haven't said what year/model your truck is, there are 2 different dim dip systems 7 neither are legally required in the UK. the lighting reg for dim dip was recinded a few years ago. Hi Western, Sorry forgot to mention the useful! Its a 1997 Defender 110 300tdi......this problem is occuring with all lights off and the engine running. Ziggy Quote Link to comment Share on other sites More sharing options...
western Posted June 20, 2011 Share Posted June 20, 2011 could be the dim dip relay/resistor relay is IIRC behind the instrument panel & has a pink case resistor is in the right rear corner of engine bay bolted to the rear edge of the inner wing outboard of the brake servo. pull the relay & join theIIRC 2 blue/red wires, that should disable the dimdip & give you normal road lighting. which bit of cornwall are you at ? I'm near Pool. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 20, 2011 Author Share Posted June 20, 2011 pull the relay & join theIIRC 2 blue/red wires, that should disable the dimdip & give you normal road lighting. which bit of cornwall are you at ? I'm near Pool. Ere! I'm not too much further west, near Penzance. Excuse my dumbness but what actually is the dim/dip....in fact looking at the circuit diagram I'm wondering why its so complicated. Your saying I can just do-away and bypass the relay by connecting those two wires straight through? Cheers Quote Link to comment Share on other sites More sharing options...
western Posted June 20, 2011 Share Posted June 20, 2011 Dim Dip was brought in by EU/UK vehicle lighting regs to prevent vehicles being driven in bulit up areas on side lights only, the purpose was to make vehicles more visible to pedestrians when it was OK to drive on sidelights, it lights the dip beam filament at reduced power to give a glow approx 1/10th of normal dip beam, Yes, the system is no longer required in UK, so it can be disabled by removing the dim dip relay & IIRC joining the 2 blue/red dip beam wires. so normal dip works. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 20, 2011 Author Share Posted June 20, 2011 I cant help thinking it has to be the main lighting switch as it is here where power is first distributed........although I accept that a separate direct (although via resister) feed is run to the dimdip relay. So by disconnecting the dimdip relay, and blanking off all the other 5 wires and connecting the 2 blue/red ones I can see how it bypasses the dim system. If I do that and the fault re-occurs I guess it has to be the switch. Quote Link to comment Share on other sites More sharing options...
western Posted June 20, 2011 Share Posted June 20, 2011 you can isolate the side/headlight switch by unplugging it & then see what happens. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 21, 2011 Author Share Posted June 21, 2011 Arrrghh! I got a feeling this problem is worse than originally thought. I haven't disconnected the lighting stalk yet but I have noticed the problem is not random/intermitant.....it ONLY happens when I put the brakes on. I.e when I apply the brake pedal the side and headlights randomly flash on and off. I cant see how the brake circuit is connected to the lighting circuit which makes me think theres a dodgy short/connection somewhere! Maybe I'll re post given I have just learned this new rather interesting fact. Any ideas people? Thanks as always Ziggy Quote Link to comment Share on other sites More sharing options...
western Posted June 21, 2011 Share Posted June 21, 2011 Ziggy, on the bulkhead inboard of the brake servo is a bunch of black earth wires, disconnect from the bolt or screw & clean the lot & refit then coat with vaseline to keep any moisture out. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 21, 2011 Author Share Posted June 21, 2011 Ziggy, on the bulkhead inboard of the brake servo is a bunch of black earth wires, disconnect from the bolt or screw & clean the lot & refit then coat with vaseline to keep any moisture out. Will do. Thanks again. I wondered given that separate circuits are involved if this was an earthing issue. I did of course when I cleaned my engine the other day get moisture inside. I didn't use a pressure washer but I did spash around a lot with a hose. I still don't understand how an Earthing fault can cause things to come on though???? Surely if the earths are bad things wont come on. That said even though I have a basic electronics understanding they always present mysteries...... Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 ..... I still don't understand how an Earthing fault can cause things to come on though???? Surely if the earths are bad things wont come on. That said even though I have a basic electronics understanding they always present mysteries...... Bad earth allows the dead to rise and they start flicking your switches when you aren't looking... Or more plausibly electricity always finds the path of least resisitance, so if there is a high resistance on the normal earth point due to corrosion it may find another path via other components causing them to turn on, remember the bunched earths may have poor contact to the body and battery but good contact to each other and as a result when something is turned on that earth bundle may be raised to 12v. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 22, 2011 Author Share Posted June 22, 2011 Bad earth allows the dead to rise and they start flicking your switches when you aren't looking... Or more plausibly electricity always finds the path of least resisitance, so if there is a high resistance on the normal earth point due to corrosion it may find another path via other components causing them to turn on, remember the bunched earths may have poor contact to the body and battery but good contact to each other and as a result when something is turned on that earth bundle may be raised to 12v. Hmmm....I got excited as yours and Westerns suggestions made logical sense. I cleaned up the bulkhead earth but it looked fine. No change. I then thought: hold on the fault occurs when I apply the brake peddle and I know for a fact having studied the diagrams so much now that the brakelights (and tail + reversing number plate light) earth at a separate point......namely 2 earths on the RH of gearbox. SO I cleaned these up and reconnected. PROBLEM STILL OCCURS !!!! Note that all electrics seem to work fine....i.e they operate when I apply the respective switch. The problem seems to be purely linked to the brake pedal and the headlights. I have a new theory!!!! I am assuming the earths are good (possibly a fatal assumption). Looking at the circuit diagrams I examined the brake pedal which comes from fuse 17. I note also that the reversing lamp AND also the ECU-EGR and MODULATOR-EGR come of this fuse also. Now my LR has had the EGR removed and blanked off but there are (at least two that I know of) loose connectors in the engine bay that were once attached to EGR related things. Theres a 2 pin connector close to where the EGR would have been and a 3-pin connector next to the injector pump. Maybe, just maybe these are fouled and shorting somewhere. I still have no idea why this would activate my headlights but it seems coincidental that these disconnected connectors are on the brake circuit and I probably spraye them with water! Any thougfhts on this welcomed! Cheers Ziggy Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Well it's worth a shot, a good shot of WD40 to displace any water or carp in the connector then clean it up and seal it in some way, it won't do any harm. Another theory could be related to damaged insulation on some cables in the loom, maybe they have rubbed somewhere and are shorting out hence the interaction between different circuits, it's possible that some moisture is giving it a hand as well. It may be worth using a multimeter to see if there is some kind of short going on between the circuits. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 22, 2011 Author Share Posted June 22, 2011 Well it's worth a shot, a good shot of WD40 to displace any water or carp in the connector then clean it up and seal it in some way, it won't do any harm. Another theory could be related to damaged insulation on some cables in the loom, maybe they have rubbed somewhere and are shorting out hence the interaction between different circuits, it's possible that some moisture is giving it a hand as well. It may be worth using a multimeter to see if there is some kind of short going on between the circuits. Damaged loom is my dreaded worst fear. As for using a multimeter to check for shorts, my concern is with everything being earthed to one I ionvariable find continuity between everything and anything. Clearly I should be using the multimeter probes at very specific points, but which ones? I guess the fuse box is an obvious place where all the circuits are close to each other!?!? This is driving me mad. I may have to become a Volvo driver and just have my headlights switched on at all times ......but I'd prefer to solve the problem. I daren't go to an autoelectrician as this king of fault is an excuse to quote any kind of large amount! Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 You need to look for points on the diagrams where there shouldn't be power unless the switch is on, if that makes sense, an example would be the wire going from the switch to the coil of a relay. It can be a bit of a nightmare but working methodically through a bundle of wires making a note of what you have tested and what reading you got really helps. Also there will be things that naturally will cause what appears to be continuity between wires, again this may be coils of relays etc, so it might help to unplug relays and fuses before testing to help save you getting false results, just remember what went where! digital cameras can be a god send . Quote Link to comment Share on other sites More sharing options...
western Posted June 22, 2011 Share Posted June 22, 2011 in the rear corners behind the light covers, IIRC each set of rear lights has a earth in there. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 22, 2011 Author Share Posted June 22, 2011 in the rear corners behind the light covers, IIRC each set of rear lights has a earth in there. I'll check.....on the wiring diagrams they appear earthed to the gearbox which seems a little odd. Furthermore those two earth leads seem to come from the front and not the rear. It seems strange that they run the tail light earths all the way to the front earth header and then back to the gearbox earthing point! Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 23, 2011 Author Share Posted June 23, 2011 Fingers crossed I reckon I've solved it and learned many another thing! Exxamined the rear harness and found where it pops up in the rear panel where the trailor harness joins and followed and checked the harness as it states in the RAVE circuit diagram. All looked good and I'm confident of all earthing. So attempted to check and isolate each circuit. I decided to start at the end of the chassis harniss which I had found and yo and behold there did seem to be a short somewhere (!!!!) between the brake lights and the sidelights. I assumed somewhere in the harness which could be alot of wire given they run from the front bulkhead to rear chasis in one main bundle! By complete chance I also spied a blue wire in behind the tailamp which was not in any diagram, so I unscrewed the tailamp to get a good look from a better angle. In doing so I disconnected the whole RH rear tailight unit. About half an hour later I fired her up to test some circuits and just did the quick footbrake test and no flashing headlights lights! Unbelivably the only thing different I have done is have no rear tail/brake ligth connected. Examine the bulb and the brake light filament has somehow got an extra bit tailing off it which is touching one of the pins on the tailamp filament so of course whenever I apply the brake 12V gets into the sidelights citcuit! A joker BULB!!!!! Whats even odder is that it hasn't blown.....each filamennt is working but just touching each other (I'll try and post a photo) Phew! Get a new bulb in the morning and hopefully end of problem. Also learned that the strange blue wire was coming of a purple wire in the rear harness which I think is used for the interior rear lighting in a 110CSW.........I haven't found what this wire powers yet as it disappears under the panelling of my fold out bed. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 23, 2011 Share Posted June 23, 2011 That is a brilliant result! I'd not have thought of a working bulb causing the problem, well spotted I believe (from memory) the purple wire is a permanent fused 12v supply and often used for accessory wiring... except on mine because it's broken somewhere in the chassis Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted June 24, 2011 Author Share Posted June 24, 2011 That is a brilliant result! I'd not have thought of a working bulb causing the problem, well spotted I believe (from memory) the purple wire is a permanent fused 12v supply and often used for accessory wiring... except on mine because it's broken somewhere in the chassis Solve one thing and discover another million! Indeed CrazyWabbit this is a brilliant result, and without ladyluck on my side this time it could have taken ages!!!! I agree on the purple wire. It is part of the original harness/loom and is a direct feed from a fuse. Interestingly mine is not live so I probably have a break identical to yours! Whatever is plugged into it will not be getting power thats for sure. I've definitely found that this wire was used by landrover for 110CSW which have a rear internal light that activates on rear door opening. I dont have this. The LR was original a utility lR for Northern Electric. I am guessing they used this feed for there own stuff which is now long gone. I have just discovered 2 identical looking blue wires (non-LR) coming into the centre console on the dash so I am guessing there was something else controlled by a switch here. Off to get a new bulb now! And a few spares!! Cheers! Quote Link to comment Share on other sites More sharing options...
western Posted June 24, 2011 Share Posted June 24, 2011 Glad you found the problem & a fix for it, Quote Link to comment Share on other sites More sharing options...
Tanuki Posted June 24, 2011 Share Posted June 24, 2011 Result! Reminds me of the problem I had a couple of years back on my Defender: the nearside sidelights kept going out with a blown fuse. Eventually tracked down to one of the number-plate-light bulbs - which worked just fine 99.99% of the time but would occasionally turn into a dead-short and take out the fuse. Disconnecting the number-plate-light [OK. It's illegal. But nobody caught me!] revealed the problem. I threw away the two 5-watt bulbs and fitted one 10-watt one. Job Done! --Tanuki. "One of my lifelong passions has been converting vegetarians back to the way-of-meat, usually through the judicious application of the fragrance from slowly frying bacon" Quote Link to comment Share on other sites More sharing options...
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