LT TDCI electrical issues

marg99 · 15-11-2008, 02:07 PM

Guys, I cannot find any similar electrical issues on the forum so wondered if anyone has a fix for this issue?

While driving along at 80klm the brake warning light came on ( the one that indicates the hand brake is on) and the interior dome light also came on. I then noticed we had no indicators/hazard lights or cruise control but did have fan radio etc although the electrical clutch on the air compressor pump did not seem to be engaging. The trip computer display also seemed to be affected. This fault self corrected after 30 minutes but also saw the engine warning light come on and stay that way. After driving for about another 30 minutes it suddenly all started working but failed again after about 20 minutes.
I have it booked into the ford dealer for monday but their immediate hope was a loose battery terminal which turned out not to be the case.

819_FLY · 15-11-2008, 02:12 PM

My suspicion is there is either a loose earth, or heaven forbid a short in the wiring near the fuse panel.... wiring diagrams would make things infinitely easier so you could see where the earths are and how many there are, there should be more than earth for the wiring and if guesses are correct they should be using a bus for earthing or a common point for most of the wiring, which would see a lot of the problems rectified.

RJO89 · 15-11-2008, 02:19 PM

hmm. My guess would also be a loose earth connection somewhere that's shorting out. Can't think of which one it would be though. Try taking off the driver side kick panel next to the clutch. There's a panel that covers the front half of the dash that can be easily removed with a T10 torx bit. Then it unclips and if you look up towards the gear shift, there's an earth connection there. Check that one. It's the only one I can think of, because I know it controls a few circuits.

Mullett · 16-11-2008, 02:20 PM

Urgh, electrical gremlins! It could also be a fault of the processing unit which controls all of those lights, I imagine there's a unit somewhere which specifically looks after all the dashlights/wipers/interior stuff.

Edit: A voltage regulator failing will also do all kinds of crazy things, and it's pretty easy to check. Just put a multimeter on the battery and run the engine at different RPMs. If the voltage moves much from 13.8 (or spikes up and down) you've got a problem in the charge curcuit.

-RM.

marg99 · 17-11-2008, 06:53 PM

the dealer says the car fault was recorded as "Communication Failure" by the ECU. Since it (predictably) was not playing up when they had it they could find anything to fix but fiddled with the wiring loom connections just in case.

Mullett · 17-11-2008, 09:53 PM

I'd guess that's only a small part of the problem, more a symptom than anything. As far as i know the ECU doesn't control the interor/dashlights/AC, but there's a seperate processor unit which does (possibly the dash cluster computer), so the fault recorded by the ECM is more than likely a symptom of a larger electrical problem.

-RM.

marg99 · 18-11-2008, 11:07 AM

that does not sound good! All I need to do is wait till it reoccurs and hope it stays that way till I get to the dealer...

marg99 · 17-02-2009, 09:52 PM

UPDATE:
fortunately dealer confirmed the ECU had an error message saying contact lost. They pulled the wiring loom connectors apart and re connected them. Worked fine for 2 months and has just reoccurred. main problem is you loose turn indicators ( and aircon, cruise control, outside temp)