Electrical Gremlins - Fuse 7

[RUSSELLM]

I’m surprised they didn’t fuse some of the outputs on those modules.

It would save them burning out when you get a wiper/window/door motor fault, lamp blowing etc...

[Penelope Stopit]

Jhonno said:

I though disturbing the loom had as well, but it is back and I can't recreate it, so perhaps it was human error.

There is 2 lights boxes. Both of mine are hardwired earth and battery, as at some point they burned out in previous ownership of the car.

Ok then

You could still follow RUSSELLM's advice (disconnect ECU's) as long as the green ignition cables aren't hard-wired, remove the green cables terminals from the ECU's plugs if not being able to unplug the ECU's

If the above isn't possible you will obviously need to cut the green cables and rejoin later once the fault is found

Diagram shows 3 ECU's, top and bottom ECU's have a sidelight cable

Meant to ask earlier but forgot.....Do the sidelights illuminate at the same time as the instrument cluster does when the faults on the vehicle?

[Jhonno]

OK, so my headlights aren't working on the dial now..

I've started to plug stuff back in, main beam works off the steering wheel, but nothing off the headlights. No dash illumination either.

If I switch the ribbon orientation I get a buzz from the box, but the other way. Nothing.

[Jhonno]

On B4 in the headlight ECU above I have a constant unchanging 0.5v on the dipped beam signal wire.

On B5 the main beam, I have 12v, until I press the main beam button and I get 0v essentially (iirc).

[Jhonno]

Foglight signal wire I get 0v, then 0.5v when the button is pressed.

[Jhonno]

OK, so.. I've had the ignition on for ages, no issues.

Closed the passenger door and Fuse 7 popped. It is now popping whenever I put a fuse back in ignition on or off.

Passenger door still works fine. Driver's door no longer releases.

Unplugging the door/window module makes no difference, it still blows.

Edited by Jhonno on Monday 6th July 19:43

[Jhonno]

I've found the culprit!



Unplug this and the fuse blow goes away.

As does the ground to earth on Fuse 7.

[Jhonno]

I still have no lights atm, but.. This wire is for the passenger rear interior light. The short is somewhere between the plug pictured and the light itself.

[RUSSELLM]

What’s that Black plastic square, on the end of the Red wire ?

I take it you’ve took the bulb out of that rear light ?

[Jhonno]

RUSSELLM said:

What’s that Black plastic square, on the end of the Red wire ?

I take it you’ve took the bulb out of that rear light ?

It's the other half of the connector..

I've removed the interior light completely and the fuse still blows if you plug this back together. There is no continuity between earth and 12v on Fuse 7 with this unplugged and the light removed.

Down side is the interior lights don't work now. And I need to work out why I've lost my headlights..

Edited by Jhonno on Tuesday 7th July 10:09

[Jhonno]

Chaffed wired in the A pillar, as it goes round the cage.

[RUSSELLM]

Good find.

[Jhonno]

Just need to work out why I've lost my headlights now!

[camel_landy]

Jhonno said:

Just need to work out why I've lost my headlights now!

Probably a blown fuse...

M

[Jhonno]

camel_landy said:

Jhonno said:

Just need to work out why I've lost my headlights now!

Probably a blown fuse...

M

[Jhonno]

So it hasn't finished with me yet..

a) no headlights/tail lights, main beam/indicators/reverse light all fine. Not checked brake lights.

b) locked it up for the night, and when you alarm it, all normal, 4 flashes, windows go up etc. Small pause. Hazards start flashing slowly.


Pass the Swan Vestas!

[Penelope Stopit]

Good find of the short

[Jhonno]

For reference I have lights back.. It was the ribbon cable given up and has a break in it. Robbed the fog light one for now, but need to find a source to replace.

[Penelope Stopit]

https://tvr-parts.com/tvr-news/cerbera-steering-wh...

[DCerebrate]

You might want to replace other ribbon cable at the same time as deterioration is age related. I had a recurring problem with steering wheel functions, it all had to be pulled apart again, and a second (lower) ribbon cable replaced. If clarification needed, TVR parts would advise as to which goes where.
R