1965 Olds 442 - Suddenly the left (drivers) side blinker and brake light are not working. Here is what I know.

- Right Side lights all works perfect.
- Left Rear Tail light illuminates with regular running lights on.
- With left blinker on, instrument panel blinker light is constant. I do also get 12 V to tail light socket with blinker on, but blinker filament on bulb does not light. So socket does get power with blinker on.
- The front left bulb illuminates with parking lights on, and brightened with blinker on, so the front bulb seems to be good.
- Left Brake light does not light as well.

I changed the rear bulb, no change. I tried jiggling the rear socket to see if it was a grounding issue but no change. Plus if it were a ground issue I don't think the running light would work either.

Last thing would be the flasher, but not sure if the right side blinker would work if flasher was bad. Could only one side of the flasher be bad?

 

It's the bulb, or it's connection to the socket.

 

The LR bulb should be a dual element 1157 (or something like that). The brake/turn filament is burned out and causes the flasher to not flash (old-school way of fault indication: If the turn signal doesn't blink on one side, one of the bulbs is burned out). There's only one way to insert it properly. It may be possible to insert a single element bulb, but it won't work properly. Check the socket contacts also to be sure they are not corroded. Double-check the ground for that socket, if it is bad, the brake /blinker circuit will attempt to drive both filaments in series and give you similar symptoms.

 

Thanks for the replies. It has the correct 1157 bulb, which is good. I changed to a new bulb to be sure. No change. I also changed the socket, no change. I'll try removing the socket from the housing, ground it separately to see if that works.

Again, this is something that suddenly stopped working while out for a drive. It has worked fine for 15 years.

 

The single flasher unit works both left and right turn signals. If it works on the right side, its good. It IS designed to NOT blink if one of the lamps on one side has blown (either the tail light(s) or the front turn signal(s)). An open circuit some where will cause the same symptoms.

Does the socket have a separate ground wire, or does it ground though its mechanical mount to the taillight assembly? If the latter, be sure it is getting a good ground (using a DMM on OHMS, measure the resistance between the socket ground, when it is mounted in the taillight assembly, and the body ground, it should measure less than 1 ohm).

If you are getting 12V on both "tangs" in the bottom of the socket (1 gets 12V when the running lights are on, the other gets 12V when the brakes or turn signal is on) and you are getting a good ground at the socket, the light should work.

 

If you have voltage on both terminals in the socket with the brake/turnsignal and the headlights on, then the bulb is not coming in contact with the terminals inside the socket, or a loss of ground. If you have no voltage for the brake/turnsignal terminal the issue is either wiring or the turnsignal switch.

 

I agree. A common problem is that the contacts inside the socket have no spring behind them. The arc in metal is the only thing that makes them high enough in the socket to contact the bulb. Sometimes the arc flattens and it does not make contact. To fix you MUST have the lights all off and you can pull up slightly on the arc to make it higher with a hooked pick tool.