Electrical Issue with Fuse#4 circuit

[Roberto]

Dropped the transmission (gearbox) to deal with oil leak at rear crankshaft to discover it was the gasket that was shot! Anyway, replaced the pilot bearing and oil seal when in there. Put everything back together as per usual instructions but alas no stop lights or indicators. All bulbs and fuses are good, everything else works including flashers.
I suspect maybe a ground fault and something to do with fuse #4 circuit since stop lights and indicators are inoperable? Any particular place I should look?

Robert
Belfast

[Jonathan]

Perhaps something came loose with the bulkhead connectors? The one with the brake lights and turn signals is the black connector. It also includes the engine bay light. Does your engine bay light work?

[Roberto]

Perhaps something came loose with the bulkhead connectors? The one with the brake lights and turn signals is the black connector. It also includes the engine bay light. Does your engine bay light work?

Engine bay light works so don't think it's the bulkhead connectors as all the other lights work; engine bay light, reverse light, license plate lights, left and right tail lights. It's just the stop lights and directional lights that have stopped working...

Any help or advice much appreciated.

[Jonathan]

For the stop lights, have you tried to look at the switch underneath the driver's footwell that the brake pedal presses into? Maybe it got disconnected.

For the directional lights, do the ones at the front of the car work if you put your signal on for a left or right turn? Just wondering if it is front and back or just the rear. Also, if you press the hazards switch, do all four of those lights blink on and off?

If it isn't something in common that's the problem, it's either separate (and odd) or it happened because of the same thing like maybe things got worked on under the steering wheel and the electrical switches got bumped.

[NckT]

The 2 circuits you describe both come from fuse 4 via the solid green wire:

Pull the brake switch electrical connector/ or hazard warning light switch off, and with the ignition key in position 2 (to energise the main relay) check that you get 12v at the solid green wire.

If you can, always connect the black lead of the multimeter to the negative battery post, but if not, then a guaranteed earth reference on the car.

(Note that the hazards are fed from fuse 6 when the hazard key is actually pressed in.)

If you don't get 12v at the solid green wire, then pull fuse 4 out and check that you get 12v at one of the fuse 4 holder in the fuse box. If you do get 12v at the fuse 4 holder and the fuse is definitely good (by checking it with a multimeter and not just by looking at it), then you'll have a wiring problem with the green wire.

(I'm assuming that the indicator lights flash with the hazard light switch pressed in and that the sidelights work front and rear to verify that the earth at the rear light boards are ok)

Good luck

Nick

[NckT]

I meant to say the "hazard switch", not "hazard key"

[Roberto]

Ok took Nick's advice. Very little voltage at brake pedal switch. Hazards working fine. No indicators front or rear. No brake lights.
Fuse#4 looked ok and checked ok. However upon much closer inspection of the fuse box there was a partial meltdown in the fuse holder!
20170730_162620_resized.jpg

(I had a previous meltdown with fuse#15 (Headlamps) a few years ago and subsequently introduced new headlamp switch bypass relay.)

I cleaned up the fuse box connection and hey presto all indicators and stop lights are working!
I suspect that during the clutch bleeding process some of the wires behind the pedals got caught on someone's foot. In particular I have a loose cable for a rear fog light in there that connects back to the rear light cluster. When this was installed back in 1991 I didn't fit any rectifier diodes, so will update this asap.

So advice is; apart from changing fuses on a regular basis it is important to check the integrity of the actual fuse box!

Thanks for your help - much appreciated.

Robert
Belfast

[NckT]

You're welcome