How many chumps does it take to find a faulty lightbulb?

Dear Car Talk

Dear Car Talk | Aug 01, 1991

Dear Tom and Ray:

I have a 1987 Olds Cutlass Cruiser station wagon. The problem is when I go to town (about five miles away), the turn signals on my dashboard work fine. But on my way back, the right turn signal will light up, and not blink. If I hit a bumpy section of road or slam my right rear door, the signal will blink again. What causes this?

TOM: This is a nice, simple problem, Mike. It's just going to require a little investigation on your part.

RAY: When the dashboard flasher lights up and doesn't blink, that means that one of the bulbs isn't working. And unlike the lightbulbs in your house--which either work or don't work--a car's directional light can work intermittently. That's because as you drive, things move and shake, and get corroded by water. And unless you live in the Bay Area, that shouldn't be happening to your house.

TOM: So the first thing you have to do, Mike, is figure out which bulb it is. Next time it happens, get out of the car and see if the right front or right rear bulb isn't lit up. By the way, Mike, do this when the car is stopped if at all possible.

RAY: Once you determine which light isn't working, the first thing you can try is replacing the bulb, which could have a cracked filament.

TOM: If that doesn't fix it, ask your mechanic to clean or replace the bulb socket and check the connection to the socket. A corroded or loose connection there could also cause intermittent flashing.

RAY: My brother used to have a problem with intermittent flashing, but we solved it by taking away his raincoat. Anyway, Mike, if all that fails, it could also be the wire that runs to the outside light. But unless the car's been in an accident, that's not very likely. I suspect it's going to be one of the simple things. Good luck finding it.

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