Quote:
Originally Posted by Peter Serio
Post #4 above has a really good info it it. Just go right back to the basics. The way that indicator is wired in the dash it depends on EVERYTHING else on the car that has anything at all to do with the running lamps, and the turn signals; bulbs (both front as well as rear) this includes ALL of the rear brake lights. All the housing sockets and grounds, & all the #1157 bulbs; everything has to be 100% for that one #1895 dash bulb to "light up" in both directions.
Once at the shop a car came in with a turn signal problem: the LF turn signal light would not work.
It was an older Buick so they gave it to me. I tracked down some of the wiring as well as testing the switch and the brake-light bulbs. When I got up front; the strangest thing. The car's owner had taken it to a local gas station to see if they could fix it first. And I guess somebody there started replacing bulbs, and they had crammed an #1156 bulb into the LF turn signal housing where an #1157 should have been. I guess an easy mistake to make since both of those are clear light bulbs. (The front lens on that car had the amber tint to it molded in.) I am pretty sure that I must have first cleaned all the ground touch-points as well and when I put a new #1157 bulb into the front TS housing everything thing started working just fine!
Those crimped steel housings do not last, just ask any '68 GTO owner!!!
It is very common for those sockets to become "un-grounded" from their steel housing, especially on a 50 year old car. The housing is the ground pathway for the bulb(s).
That or one of those springs underneath the 2 copper buttons will rust and crack in 1/2. And so basically you have an open in your + circuit which you cannot see. (GM used to make a little repair kit for those copper buttons and the springs.)
I am pretty sure that kit was specifically made to fix 1968 Lemans & GTO tail lamp sockets at first but you could easily use the parts from that kit to fix other GM cars as well.
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Agreed! I just replaced my backup light switch and re-wired, then noticed only the passenger bulb lit (hadn't checked before working on the switch). I removed the lens cover and started wiggling the bulb and it flashed on sometimes depending on position/pressure. No cleanup of the socket would guarantee proper function, so I then ran a ground wire directly to the housing from the bumper frame mount bolt and now it works every time. Assuming these old housings will keep providing a good ground path may drive you crazy and I wasn't looking to replace the original unit and don't expect any judging on my wiring anytime soon!