Board logo

Earth fault ?
clairetoo - 28/5/08 at 02:30 PM

I just tried to pull my car uot of the garage , and when I touched the brakes the engine died......the brake lights are turning the ignition off , and there is no oil light as well as the indicators not working
It was fine when I put it away last night , all I`ve done to it today is free off a stuck caliper - any electrical guru`s out there ? I`ve no idea where to even start looking..........


mookaloid - 28/5/08 at 02:41 PM

It sounds like a dodgy earth somewhere - I would check all the points where the loom earths to the chassis first.

Cheers

mark


ravingfool - 28/5/08 at 02:42 PM

electrickery is the sign of the devil. I'd start by disconnecting your battery and main earth connections, clean them all up and reassemble. My B was doing some strange things a couple of weeks ago, did this and all cured, I think in my case the battery - chassis connection was just a bit dirty.

And in any case making sure of these good connections will start to narrow down the search by ticking off the simple things, and that's got to be the correct way round to go through the list of possibilities!


Mr Whippy - 28/5/08 at 02:42 PM

well that’s a new one to say the least...

have you perhaps got a wire too close to the pedal and its getting pulled on? a bit odd this one


theconrodkid - 28/5/08 at 02:43 PM

ignition light not working as well?,sounds like an engine earth fault (assume you have main earth lead engine to battery)


clairetoo - 28/5/08 at 02:47 PM

Things that do work are -
The engine - stars and runs fine , charges fine .
Lights - all present and correct
Fuel gauge is fine .

I allready had a fault like this on the reverse light (engine cutting when put into reverse) so I just disconnected the switch......


worX - 28/5/08 at 02:48 PM

Then it's obvious what to do - Disconnect the brakes...
Steve

quote:
Originally posted by clairetoo
Things that do work are -
The engine - stars and runs fine , charges fine .
Lights - all present and correct
Fuel gauge is fine .

I allready had a fault like this on the reverse light (engine cutting when put into reverse) so I just disconnected the switch......


clairetoo - 28/5/08 at 02:55 PM

quote:
Originally posted by worX
Then it's obvious what to do - Disconnect the brakes...
Steve


I allready try to avoid using them as much as possible

I`ve just checked the fuse box , and there is no power at the fuse ? But I do have earth continuity from the fuse ....... maybe the ignition switch ?


Paul TigerB6 - 28/5/08 at 03:05 PM

I blame them damn pixies!!!

Check the connections on the back of the fusebox. They have been known to come out. Can you get the multimeter to the back of the fuse box at all?? Check continuity from there to the ignition switch (on the live side obviously)


Mr Whippy - 28/5/08 at 03:23 PM

sounds like your going to have to trace the brake wire back and see were its getting its power from, I suspect the brake light switch is earthing you ignition circuit.


clairetoo - 28/5/08 at 03:43 PM

I`ve checked every connection on the brake light and indicator circuits.........and cant find anything wrong
So I got out my reading glasses and studied the wiring diagram........ The flasher relay gets its power through the hazard switch , so I tried that - and the hazards work fine . Thing is , the indicators were `on` when I did that , and when I switched off the hazards the indicators stayed working.......and now work fine
The brake lights work fine , even the reverse light is working fine now

I think I might just need to completely re-wire the whole damn car when I get back from France


Paul TigerB6 - 28/5/08 at 04:06 PM

Might be worth just cleaning up all the earthing points on the chassis and accessible contacts to that circuit then - odds on you just touched a wire and got it to earth / contact better


Mr Whippy - 28/5/08 at 04:26 PM

quote:
Originally posted by Paul TigerB6
Might be worth just cleaning up all the earthing points on the chassis and accessible contacts to that circuit then - odds on you just touched a wire and got it to earth / contact better


hmm I tend to agree, if the car works fine, goes weird then works fine again...its a bad earth. Check the main battery earth strap connections they tend to corrode quite quickly.


jacko - 28/5/08 at 04:31 PM

Have you been driving in the rain ? is there water in any of the lamps that could earth it out
Jacko


fesycresy - 28/5/08 at 05:23 PM

quote:
Originally posted by jacko
Have you been driving in the rain ? is there water in any of the lamps that could earth it out
Jacko


Agreed.

Had a car in the past that if i kept my foot on the brake I could take out the ignition keys and it would still run.

Take the foot off the brake and she's stop !

It was a rear bulb earth !!


02GF74 - 29/5/08 at 07:54 AM

check battery connections are clean and tight - the sudden deceleration may be moving the cables to the battery so you lose contact.


clairetoo - 29/5/08 at 08:02 AM

This was at a stand-still I think the problem was/is a dodgy hazard switch - I da a good(? in the rain?) drive out last night , and it didnt repeat.........fingers crossed for France tomorrow......


Macbeast - 29/5/08 at 04:49 PM

It could also be a poor connection on the live side . When you brake the light puts extra load on the switched ignition feed and drops the volts.

Take a multimeter with you and bonne chance