Driving to work this morning when the following happened:

 

Transmission oil warning light came on,

Diff oil warning lights came on,

Failed light bulb warning light came on,

Battery light glows faintly,

Turbo guage stuck to the far left of the guage.

 

The odd thing is that all the above lights normally come on with the ignition key then go off when the engine is started. Now they don't come on with the ignition key but light up AFTER the engine is started!

 

Car drives fine and the boost level reads fine on the AVC-R. However, it does seem slightly unhappier idling than before.

 

Measured the voltage across the battery. !3v with engine off. 14.1v with engine on.

 

Any ideas?

Could be an earthing problem

Could be an earthing problem

Thought about that but the wiring loom that this is a part of (main internal loom) is earthed in several places and, as far as I know, is shared between all the devices in the loom.

 

The two oil level warning lights share the same diode pack in the passenger footwell so I though I'd try disconnecting that to see what it affected. And as you'd expect, it just stops those two lights lighting up at all. Big news!

 

It's really got me this one.

Thought about that but the wiring loom that this is a part of (main internal loom) is earthed in several places and, as far as I know, is shared between all the devices in the loom.

 

The two oil level warning lights share the same diode pack in the passenger footwell so I though I'd try disconnecting that to see what it affected. And as you'd expect, it just stops those two lights lighting up at all. Big news!

 

It's really got me this one.

 

Engine to chassis earth???

Maybe your transmission and diff oil. your lights and your battery, as well as your Turbos have all chosen to die cos they didn't want to go to work!!!

 

Joking aside, I had a loose multiplug that did sommat like that behind the speedo. Gives you the screaming ad dabs when it happens though, doesn't it?

 

Took 15 minutes to fix

 

Chris Davies

I've spent the last few weekends stripping bits of dashboard to pieces and putting it back together again, lying under the car inspecting the sensors, etc, with no joy whatsoever.

 

So today I spent a few hours pouring over the wiring diagrams. And what a donkey's ar5e I feel now... should have done this in the first place.

 

The afore mentioned warning lights all pass through a single relay. This relay shares the same power supply as the boost sensor. And all this passes through a single fuse.

 

So oddly enough, when I checked the fuse it had blown. Fitted a new one and everything's alright again.

 

And the dodgy idling... the fuse also feeds a power supply into the engine management system. Quite why the car carried on working at all I don't know. Even showed a code 55 (all clear) while the problem was there! Idling is fine again now with the new fuse.

 

So next time I've got a dodgy electrical problem I can't diagnose, I'm simply going to remove every fuse in the whole car and test it before I start stripping things out!

Glad yer got it sorted mate, but which fuse and where was it that caused this fella ?

cheers

smithy

Glad yer got it sorted mate, but which fuse and where was it that caused this fella ?

cheers

smithy

It's in the fuse box in the engine compartment on the passenger side (the one you've done some shiny cover for!). It's dark now and I've had a few beers so I can't be ar5ed looking until tomorrow. However, it's the one at the front of the car nearest the engine.

That's okay mate know which one yer mean now, many thanks

cheers

smithy

Ok. Worked it out.

 

The fuse supplies the boost sensor, part of the engine management, the "light test" relay and the alternator light. As many of you will know, the alternator light works by having one side connected to the +ve battery side of things (and thus the alternator) and one side connected directly to the alternator. If the alternator output voltage falls below that of the battery, a potential difference exists across the warning light and it glows brighter depending on how big the difference is.

 

Now as the fuse had gone, all these devices had lost power. However, they were all drawing power from the alternator through the alternator warning light. This is why the light was glowing dimly. The voltage drop across the light meant that the other devices were receiving a reduced voltage. This sent the boost sensor totally out of range. It also allowed the other warning lights to illuminate by being a low enough voltage to fire the relay (other side connected to +ve) and a high enough voltage to allow the engine management system to work. But with the reduced voltage, this caused the unwanted side effects.

 

Thought I'd post this in case anyone was interested. You've probably all lost interest by this last line anyway!