348 Indicator/brake light problem

I see what you mean. Quite bizarre. No common plugs, earths (as far as I can see) or power sources.

You may have to treat each fault individually and hope you find something in common.

When the brake lights don't work, check to see if your windscreen wipers work (same power source)
Because you have no hazards or turn, it could mean:
1) faulty hazard/turn module.
2) faulty power relay on the back of the centre (vertical) console (bad news as they are soldered in and aren't replaceable).
3) loose plug behind the centre (vertical) console panel. Next time you have a problem, check to see if the parking light switch works with the ignition off.

 

Interesting. When I started looking at the door wiring, I noticed that there is an earth numbered "122" in the diagrams. It provides an earth for:

turn/hazard module
windshield wiper motor
driver's window control switch
driver's door lock

Where the earth is, I don't know... and I still can't relate it to the brake lights, unless there is something whacky going on with the wiper motor or wiper motor plug (power and earth wires partially shorting).

Could you try pulling fuse "5" (brake lights & wiper motor) and see if the turn & hazard is restored? That fuse also controls the door mirrors.

 

I recently replaced my stereo and while my stereo was out and the center console was out the console switchs and the switch panel above the radio were out. when I put power to everything, everything worked except my turn signals brake lights hazards that sort of thing. That circuit is wired to all of those switches one of the switches could have a bad connection.

Sent using FerrariChat.com mobile app

 

The power wires for the hazard/turn module run through the plug to that panel, so it makes sense that the turn and hazards don't work. It's the brake light not working that doesn't make sense.

Battery >> relay e >> fuse 5 >> windscreen wiper plug >> brake pedal switch >> relay panel (straight through wires only) >> brake lights.

If relay e (control relay for ignition circuits) was broken, it would affect the turn signals, but not the hazards. Also, other things wouldn't work. e.g. air conditioning.

The only thing not clear from the lighting wiring diagram is the earth for that panel near the radio. It goes from the panel to the oil temp gauge plug then disappears.

F348 Lighting Wiring Diagram

 

Found the earth (i.e. "100") on another diagram. If that earth was faulty, there would be a lot more than just hazard and turn signals not working... and it's not going to affect brake lights.

I've updated the lighting wiring diagram to show the link with earth "100". Click on the link in the previous message. Refresh browser as required to view the changes.

 

If the Relay e is faulty (or its pins are corroded), it will affect the brake lights (Fuse 5) and both, the turn signal and hazard lights (Fuse 7). At the same time, it will also affect a number of other things like:

Windscreen Wipers
Reversing Lights
And via Fuse 6:
Instruments
AC Compressor
Etc.

I would first check the Relay e.

 

Correction: Ian, you are right - faulty Relay e will affect the turn signal lights but not the hazard.