MainePorsche

Guys,
This is new. Third brake light intermittently works/fails. Checked at harness - connections and bulb look good (bulb works). Right Brake Light works fine - no recent work there.
My question is how/where do I access the loom connector that runs to it and the hatch light.
I'm guessing that fault is in the Red/Black between the Right Brake Light and the Third Brake Light, or the Brown between the Third Brake Light and MP VI. All rear lights that share MP VI work fine.

Thanks in Advance
Craig

davek9

The wires run from the CE panel along the passenger side foot well / rocker panel and then up the "B" pillar along the rear of the headliner and into the rear hatch.

You will need to remove the rear seat and then the rear quarter panel (inside the car) and pull down the back of the head liner to expose the harness. I would ohm out all point to point before pulling it apart.

Have you checked for a good connection between the CE and the Lights, you could also do this at the Lamp Control unit as that is what feeds the rear lights.

There is a connector just below the rear speaker also, I have seen where speaker installs have (drilled or screwed through that harness.

MainePorsche

Thanks davek for the line location.
As the Right Brake Light functions normally, This would mean that current from pin 11 at Lamp Control is reaching pin 6 at the 6 pin harness where a Black/Red is connected which feeds the Right Brake Light. The defect must lie distal to pin 6, or it is a ground defect.
I just got home after a Big day, and will tend to it tomorrow.
Thanks again.

davek9

You can use a 9volt transistor battery ground the negative to chassis, and use the positive to light the lights, all from the female connector at the lamp controller. Just select the correct pins per the diagram for ur model year, on an 85 / 86 it's 9 & 12 for stop. However on s4 the pins change as they monitor more than tail, rear side markers and stop.

MainePorsche

Just began going through the diagnostics and found the fault to be in the bulb harness itself. Where the bulb seats, the contact to the housing of the bulb was not contacting by a paper thickness depending on how the bulb was seated. A little adjusting to the filament contact, along with adjusting the bulb housing contact, and it's good to go. Happy about this, for I really did not want to pull the back seat to get to the connecting harness behind the liner.
Thanks davek for your input.