1965 Buick Skylark taillites

[Jerry Altenburg]

I have a 65 Skylark that just recently that when I turn the key on 2 of the 6 taillites come on and are very bright.It doesn't happen all the time.The light switch is off when it happens,but still does it with lites on the 2 lites being brighter than the other4.Can anyone HELP ME OUT with this problem? by Jerry-E'mail at lazerjj@charter.net

[Jerry Altenburg]

Jerry Altenburg

[JohnD1956]

Sounds like two problems to me. brake light switch and poor grounds at the tail light sockets. First thing to do is pull all the light bulbs and clean the contacts and the sockets they are riding in. If the bulbs and sockets are clean then follow the wires and make sure all the grounds in the trunk are clean.

The brake light switch is a different animal. I believe that is under the dash attached to the bracket that the brake pedal arm pivots on. First I would disconned this switch and then see if your problem continues to exist. If so it's most likely a short in the signal light switch in the column. If not then you might have to adjust that brake light switch or change it out.

[Aaron65]

Good advice above...When I bought mine I had to clean all of the sockets out very well, but that wouldn't cause the brake light problem...the only thing is that the brake lights light up the outer 4 lights...

[Guest brh]

It sure sounds like a bulb was replaced with the wrong one. Check your tail lights they should be 1057s, your front signals I think are 1056. Right off the bat I'd check the four inner tailights (ones closest to the emblem). Changing out wrong bulbs and bad grounds will cause some screwy problems.

[Guest John Chapman]

Jerry,

I experienced similar problems with my '65.

Easy to not so easy:

1. Check for and remove corrosion... I recommend using dielectric grease in all lamp fittings. It makes intallation and later removal easier and helps prevent moisture intrusion and corrosion.

2. Make sure you have correct bulbs. The two outboard bulbs in the tail lamps are dual fillament/circuit #1157 (running and brake/signal); the inboard bulb on each side is a single fillament/circuit #1156 (running light only). Switching these will cause some interesting problems, as the bulb contact points are in such a place that the 1156 can usually connect to both contacts in an 1157 socket.

3. Pull the fuse holder apart and check for internal grounding and shorts. These are relatively flimsy and 43 years of pulling and pushing fuses into rusty holders can create additional sources of electrical mischief.

4. These are 'one wire' cars, with the body acting as the negative/ground circit for lights. Check for grounding through the harness. This will happen if you have damaged wires someplace. Your lamps can actually ground via another hot wire by current flowing back though the 'other' hot wire to the 'other' switch/motor/lamp and then to ground through that component. Although this is technically a short, it won't usually burn fuses because is isn't a direct to ground. It flows through resistance (a lamp for example) first. Check is simple. Pull the lamp socket from the back of the lamp. Tail light housing/body supplies ground via the spring tension clips on the socket. If the lamp continues to burn with the socket out of the tail light, you have a circuit ground in the harness somewhere.

If you suspect a harness problem, it is relatively easy to troubleshoot. The rear harness for the Skylark connects to the body harness under the rear seat back on the left side of the car. Circuits that run through the rear harness: Gas gauge, backup lamps (optional, but wiring is in all cars), running lights/tag lamp, brake/signal lights, rear courtesy lights, and trunk light (optional). The harness runs along the left opening of the trunk up under the lip and can be pinched/damaged by junk in the trunk, collision damage and careless collision repair.

Disconnect the harness at the connector to the flat body buss. Remove all lamp bulbs in the rear (including the courtesy lamps)(Note: The license and backup lamps can be a pain. Consider pulling the bayonet connectors apart instead of removeing the lamps). With a circuit tester, check for continuity between any wire pairs at the rear body harness connector. There should be none. Continuity indicates an internal short in the harness. The exception is the brown wire for the gas gauge, as it goes to ground via the tank sending unit, so don't test it in your continuity checks.

In my case, I had a short between the right brake/signal, the backup lamps and the running lights. Did I have some interesting symptoms! When 12v current runs back through the available circuit to a ground (turning on other lamps enroute) it can be very puzzling, especially when unintentional grounding via the 'other ' hot circuit goes through a switch someplace (e.g. the light switch, brake light or turn signal). My fix was to replace the rear body harness with a M&H unit. Ended the lives of numerous electrical gremlins... a well spent $115!

Hope this helps!

Cheers,

JMC