unfit Posted August 6, 2016 Share Posted August 6, 2016 Hi, I have a faulty earth cable < it doesnt earth into the chassis, just the gearbox casing> this is being replaced, it is on order. I also have needed to replace bulbs, rear brakes and running lights. A rear brake I replaced 4 months ago has gone again. So, could these be linked? Thanks for any opinions. Quote Link to comment Share on other sites More sharing options...
Tal Posted August 6, 2016 Share Posted August 6, 2016 What vehicle is it and how old is it ? it could easily be related but it can also depend very heavily on what you are doing with the vehicle. Quote Link to comment Share on other sites More sharing options...
unfit Posted August 6, 2016 Author Share Posted August 6, 2016 It is a 97 plate defender 90 TDI 300, I use it for off road and commuting. Quote Link to comment Share on other sites More sharing options...
western Posted August 6, 2016 Share Posted August 6, 2016 a faulty rear brake won't be caused by a missing or poor earth cable. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 6, 2016 Share Posted August 6, 2016 Check output voltage from alternator, could be the regulator has failed, and spitting out 15+ volts! Quote Link to comment Share on other sites More sharing options...
unfit Posted August 7, 2016 Author Share Posted August 7, 2016 Hi, a recent clutch change identified or might have caused a electrical fault. a wire at the back of the engine had been rubbing, it tripped the fuse and the car would not start. this was fixed, would this have blown bulbs at the same time?? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 7, 2016 Share Posted August 7, 2016 Pretty unlikely. Quote Link to comment Share on other sites More sharing options...
AMB Posted August 7, 2016 Share Posted August 7, 2016 Bulbs generally fail on high voltage, vibration or old age. My guess would be high alternator voltage - probably poor earthing. Quote Link to comment Share on other sites More sharing options...
Tal Posted August 7, 2016 Share Posted August 7, 2016 First check the bulb holders, if they are loose from corrosion or the centre spring is sloppy they might be sparking when you're off road or pothole diving. The light earths in the back there are very close to the holders, not sure exactly where in the defender but the disco has them just above the lights attached to the bodywork so probably in a similar place. Those could be loose. Quote Link to comment Share on other sites More sharing options...
western Posted August 7, 2016 Share Posted August 7, 2016 Worth fitting a decent thickness main earth cable from engine to chassis, the existing one from battery -ve to bearboc/transfer box joint bolts is pretty standard on any 90/110. rear light have or should have seperate earth connections to the vehicle body in each rear corner behind the corner cover panels.worth making sure these are clean from corrosion & tightly bolted up. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 7, 2016 Share Posted August 7, 2016 There are only two likely reasons for repeated bulb failure. One is alternator over-voltage, as the others said. The other, more likely if you get repeated failures on one position but other bulbs are OK, is that you have a bad contact between the bulb and holder causing point heating, and leading to the element prong failing. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 7, 2016 Share Posted August 7, 2016 Agree with snagger ^^^^ Quote Link to comment Share on other sites More sharing options...
unfit Posted August 10, 2016 Author Share Posted August 10, 2016 There are only two likely reasons for repeated bulb failure. One is alternator over-voltage, as the others said. The other, more likely if you get repeated failures on one position but other bulbs are OK, is that you have a bad contact between the bulb and holder causing point heating, and leading to the element prong failing. Hi all, I have been and checked the earths, all okay. the bulb was okay in another bulb holder so I have replaced the bulb holder. Interestingly the faulty one looked okay! I have the new battery to chassis earth cable to fit next. The old one has been shortened at some point and did not stretch to the chassis, it only earthed on the gearbox! Thank you all for your help. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 10, 2016 Share Posted August 10, 2016 I think it is normal for battery to go to gearbox bellhousing bolt, there is then a further earth cable from engine/gearbox to the chassis. If you move your current one to the chassis you will end up with no decent earth for the engine, and it will fail to start or melt your clutch/speedo/throttle cable Quote Link to comment Share on other sites More sharing options...
steve b Posted August 11, 2016 Share Posted August 11, 2016 Bowie is right , the gearbox earth is the std factory main current earth for the starter. You need to run one to the chassis as well , but more importantly a smaller one direct to the bulkhead earth point near the clutch m/c. This is the main earth for all the lights and dash and will help to bypass all the dodgy bolted ally/steel joints in the bodywork. Mine has full earth returns everywhere ( I remade my own loom) and in 12 yrs. and 120k miles I've probably had 2 bulbs go ...... cheers Steveb Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted August 11, 2016 Share Posted August 11, 2016 For the same reasons as Steve above, every circuit I add, I wire in twin core so that the earth goes back to the battery negative. The tip about the bulkhead earth stud is a good one, it's the source of many a dash gremlin ? Mo Quote Link to comment Share on other sites More sharing options...
unfit Posted August 12, 2016 Author Share Posted August 12, 2016 Hi, I have a defender 90 tdi300 n reg landrover, as this was mentioned in past posts as an important point to clarify. So I have run the earth from the battery to the chassis and then it continues to the gearbox earthing point. The cable came with connection points at each end and in the middle so this was easy to do. The mechanic at the garage said that the old cable had lost one of its earth connections, it was missing the mid point connector. He also said to bolt it onto the chassis as well as the gear box. Is this wrong??? Quote Link to comment Share on other sites More sharing options...
Mutley Posted August 12, 2016 Share Posted August 12, 2016 I too have a 300tdi 90 which had starting problems as soon as temperature hit below Zero degrees, so I made up x3 individual earth cables and fitted Battery to engine case....Battery to chassis......Battery to starter motor or alternator which ever you are supposed to any way. Also had issues with rear lights blowing and for months I could not fix or find the fault!!!!..........Eventually found the problem, the wires had chaffed and were shorting out on the chassis where they run along the top just back from the front bulk head on the near side. I cut out the damaged section replace with new wire and crimps wrapped it in insulation tape then put a protective sleeve over the section and finally wire/zip tied it out of the way, have not had any issues with these wires since. The hard part is finding where it is shorting out!!! Quote Link to comment Share on other sites More sharing options...
steve b Posted August 12, 2016 Share Posted August 12, 2016 Unfit , yes that's fine , I'd still add a lighter grade of earth wire up to the bulkhead earth point , say around the thickness of the alternator current wire cheers Steveb Quote Link to comment Share on other sites More sharing options...
unfit Posted August 12, 2016 Author Share Posted August 12, 2016 ace thank you steveb. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.