Solved!: Rear Lighting Electrical Gremlins Options

[scottthephotog]

So I've been chasing electrical gremlins with the rear lighting since I bought the car a year and a half ago, and from what I can tell, the previous owner was as well (but just didn't mention it during the sale). The front lighting works as it should.

Here are the symptoms:
with the parking lights/headlights off

• The turn signals operate correctly (no pedals or other switches engaged)
• Pushing the brake pedal causes both brake lights and turn signal lights to flash simultaneously
• No reverse lights when in reverse
• turning on the emergency flasher lights flash the licence plate lights.

with the parking lights/headlights on

• Either direction on turn signal flashes both turn signal and reverse lights simultaneously
• pushing the brake pedal causes both brake lights, both turn signal lights, and both reverse lights to flash simultaneously
• turning on the emergency flasher lights cases license plate lights, turn signal and reverse lights to flash
• No reverse lights when in reverse

Things I've tried:

• Cleaning all ground points on the entire car (double checked locations with diagrams on 914World)
• Taillight bulb sockets and connectors are clean
• Checked taillight wiring against diagrams on 914World and shop manuals (I found previous owner had printed out those diagrams as well) - They are correct
• Checked headlight and hazard light switch against diagrams on 914Wolrd and shop manuals - They are correct
• New headlight switch (which it looks like the previous owner tried as he included a spare)
• The previous owner also tried different turn signal flasher relays as I have 2 spares
• The rear wiring looks like it is in good condition. I don't see any splices or breaks.

I know that the hazard light switch is also part of that system. I'm at the point of trying a different one of those, but I don't want to just throw money at random parts.


Any thoughts or suggestions? The front lights work perfectly fine, so I'm leaning towards a wiring issue. Are the front and rear lights split at the hazard light switch that part of the switch could have failed? I also can't figure out why the licence plate lights, reverse lights and brake lights are affected by this.

[ejm]

Make sure the correct bulbs are installed. A single filament where there should be a double will cause issues like this. Sometimes double filament bulbs short internally. Replace all of them or test by removing one at a time. The reverse light problem is most likely the switch.