I am
in the process of restoring my 68 cougar, and have a problem with the rear lights. they do not come on. The brake and turn signels works fine, but the tail lights do not come on. The headlights work fine. I checked the relay on the left rear quarter and am also going to replace the brake light switch. Is there a fuse located somewhere else?
Thanks LGeorg
Lgeorg,
You mention a relay on the left rear quarter panel, the relays are all for the turn signal/hazards lights and not the taillights. There is a circuit breaker mounted on the left rear taillight panel near the left taillight. Perhaps you meant circuit breaker and not relay. Anyhow, there are only 2 wires to the circuit breaker, input power from the headlight switch and output to the taillights.
But before I go into troubleshooting, verify that the taillight bulbs are 1157 dual filament bulbs, where the Low is the taillight filament and the high is the Brake/Turn signal filament. Note, the wiring up to the lights for the Taillights and the Brake/Turn lights ARE SEPERATE.
Now for a quick test, pull the headlight switch to the Parking light position (1st detent). Do the front side marker lamps illuminate? Do the license plate lights in the rear illuminate? The wiring circuit that feeds the license plate light is the same wiring circuit that eventually feeds the taillights.
If the front side markers and the license plate lights do not illuminate, then the problem is most likely with the headlight switch. If the front side marker lights illuminate but the license plate lights do not, then the problem is between the wiring after the headlight to the rear.
If your headlight switch works for the side marker lamps, but not the license plate light, place a multimeter on the input side of the circuit breaker and verify 12 volts. Remove the output wire of the circuit breaker and repeat the voltage test on the output side of the circuit breaker.
Let me know how the results of the above and we can go from there.
Good luck
Coach Jack
Thanks for your response. I will try to answer your questions in order. Yes, fuse not relay on the rear quarter. The lights in the back are new leds and did work correctly before I removed everything to have the car painted. Without a volt meter I used jumper wires to see if there was any power to the back breaker. It appears not. As I mentioned before, at the moment I have the break light switch out to replace it. Would that have any effect on the rear driving lights? As you asked before when the light switch is in the parking light position the sidelights are ok but no license plate lights.
Thanks Coach Jack
Lgeorg,
“Yes, fuse not relay on the rear quarter.” - if your wiring harness has a fuse instead of a circuit breaker, then someone has kludged your harness or has replaced it with an aftermarket harness. The 68 cougar utilized a 6A circuit breaker.
You mention that everything worked before the car was painted. Did you make certain that the ground wire at the taillight panel between both taillights is clean and connected to bare metal. Also make sure to use a star washer on this connection.
LEDS - you might want to remove the LEDS for troubleshooting purposes and plug in at least 1 1157 dual filament bulb in each left/right taillight.
If you don’t have a multimeter, you can use a testlight to check for power. I have recently added a power probe I purchased at Autozone that doubles as a voltmeter but more importantly the tool allows me to either power a circuit or ground a circuit for testing purposes.
The brake light switch plugged in or not has no affect on the taillights.
I would remove the headlight switch and test the B and R terminals for continuity when on Parking lamps mode and Headlights on. If there is no continuity here, then the headlight switch is suspect.
Let me know if I can provide you anymore assistance.
Coach Jack
The tail lamps get their ground from the nuts that secure the tail lamp assemblies to the body. If you used the new nut kit from AMK then you probably don’t have a ground. I had the same issue recently. To fix it I just used one original nut on each of the two tail lamp assemblies. It fixed the problem.
I think we have narrowed it down to the wire coming out of the harness to the rear. The electric manual shows that there is a three lead plug somewhere on the wire harness to the rear. Does anyone know it’s located. It may have been unplugged during restoration. Considering running a new wire to the rear