wtf tail lights

August 17, 2009, 09:42:42 PM

ok i put my dash back in today the only prob i see is i get no tail lights when i turn the light swich on or any brk light when i hit the brake but i get tail lights when i turn on my key....wtf

wtf tail lights

Reply #1 – August 17, 2009, 10:15:31 PM

The first thing I would check is to make sure all ground wires are connected to the metal frame on the dash. This could be a back feed problem that happens when an important ground wire connected with an eyelet is left loose or not making metal to metal contact with the metal dash frame. Voltage is going to take a path somewhere and backfeed through another circuit if the proper ground wires are not attached. This especially happens when dual filament taillamp or parking lamp bulbs share a common ground in the lamp sockets. For instance, in a dual filament taillamp socket and bulb, if the voltage for the brake lamp filament cannot pass the voltage to the ground wire on the socket because there is a poor or no ground, it will back feed through the ground wire in the taillamp socket and pass backwards through the parking/running lamp bulb filament and into that circuit until it finds a place to ground, which may happen when the ignition switch is turned on and the voltage passes through a circuit that does have a ground.

When I pulled and reinstalled the dash on my 1984, there were two very important grounds attached with eyelets that come out of the main dash wiring harness. They are attached to the metal frame of the dash at the back bottom inside the radio/hvac center stack opening. These wires provide a ground for everything that operates off the entire dash wiring harness that runs behind the instrument panel.

Without knowing much of what you have done, I cannot think of anything else to check for. The wiring harnesses are pretty much plug and play if you did not cut or splice anything into place. To me it has to be a common grounding problem. I see no other cause for that. I am assuming you have only been working with the dash area and have not disturbed any wiring or bulbs in any other part of the car.

Something else I remembered! There is also an important ground attached to the steering column. Follow the wires from the switches and be sure that is connected.

I hope this helps!