Buick Century – turn signal mystery

[Bob K]

My Buick Century ’04 (160k miles) front turn signals are misbehaving in strange ways, the symptoms have varied over the last few days, and got worse after I tried to fix them(!). All problems refer to amber bulbs in front of vehicle; rear bulbs are fine, and white side illumination lamps kick in correctly when turn signals are fired.

Symptoms (two days ago)
– Right front turn signal was flashing fast – this started months ago. Put new bulb in, but didn’t fix the problem. However, a few times I was able to fiddle with the socket in the headlight housing, and it would work for a while, but then go back to flashing fast. This makes me think the socket should be replaced. However, read on.
– Left front turn signal was fine through all of this, until 2 days ago the left dashboard indicator started staying on continuously, and the amber light would blink fast when turned on. Replaced the bulb, didn’t fix the problem.

Attempted fix
Because both amber turn signals were misbehaving, I thought it could be an issue with the flasher unit. So I replaced it today, and tried replacing the bulbs again… and things got worse!

Symptoms (today) after replacing the flasher
– With running lights on, only the right side amber bulb comes on. The left side seems dead.
– Right side turn signal doesn’t blink, and dashboard no longer blinks fast – dashboard shows normal operation, despite failure to blink in front.
– Left side turn signal doesn’t blink; dashboard no longer shows continuously-on indicator – displays normal operation, even though bulb doesn’t blink.

Questions
– Why is my dashboard indicator not indicating a problem with either side, even though both sides aren’t blinking, and earlier the indicators were blinking fast or continuously on?
– Is replacing the sockets on both sides the way to go, or do I have a bigger problem on my hands?

Thank you!

Topic

[none]

The indicator staying on as you described, suggests to me it’s got a ground problem. When a ground goes bad, it causes back feeding. Electricity is trying to find a way to ground through other circuits available to it. The sockets probably are causing your troubles. It’s fairly common to find them with burnt contacts and maybe being a little melted. Corrosion is another definitey possibility making them not work right. Start with replacing the sockets and inspect the wiring at the same time.

Good Luck.

[Bill]

Did you try turning the emergency flashers on to see if the bulbs light?

Get yourself a 12v test light and ground it. Touch the tip of the light to battery positive to be sure it works. Remove the front signal bulbs and turn the signals on. Touch the test light carefully to the contacts inside the socket to see if the light flashes. Be careful not to touch the light to ground in the socket.

If the test light flashes I would say that the sockets have lost their ground internally and need to be replaced.

If the test light doesn’t flash you either have a bad signal switch or a wiring problem.

[Bob K]

Thanks for the responses. I replaced the bulb sockets, and both turn signals are working well now. I’m glad it wasn’t the wiring! Thanks again!

[Author]

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