Left Blinker flash quick... Replace fuse?

08-08-2004, 06:05 PM

Im trying to give my mom a hand here, and she was driving her 97 buick when her left blinker started to flash extreamly fast. She got home and said, "Well I guess im going to make an apointment to get that fixed"

Seems so stupied to have something like that fixed by taking it in. I know its a fuse, but which one, where?

the blinker in the front left dosnt blink at all, but the rear left blinks quick?

Dose that make sence?

I dont have the manual or any books on it, so a hand would be great, Some one point me in the right direction.

08-09-2004, 07:15 AM
most of the time it means one of your signal bulbs are burned out

08-10-2004, 12:55 AM
Buick Turn Signal Issue - detailed answer.

This info applies to 1998 Buick Regal LS (1997.5 to 1999) I suspect.
I had this same problem and traced the problem to the contacts in the turn signal switch (in my case).
The switch itself is expensive and quite hard to access but it can be removed and cleaned manually if contact cleaner doesn't take care of it.
It's wise to disable the airbags while working around the steering column but hopefully you won't have to work on the turn signal switch because that's a complicated project.

GM did not design a simple blinker circuit. The vehicle lighting schematic covers 15 pages, really.

Fast blinking means there is less than a full current load which usually indiates a bulb may be out. Each side normally draws about 6 amps while blinking, so if one bulb is burned out, the current (measured at the turn signal fuse) will be about 3 amps on that side.

Hopefully it's just a bad bulb, but if not, here's a collection of troubleshooting info.
It's probably not a bad fuse because the same 10 amp fuse runs both sides. The fuses are located behind a small pull off panel on the right side (or end) of the dash. The fuse positions are labled on the back side of the cover. More fuses are located under the hood but those aren't directly involved here. The flasher unit is located behind the left side pull off panel.

So, this could be caused by:

1. A burned out bulb. hopefully!
2. Bad bulb socket, wiring, or a connector (it could be partially melted for example).
3. Faulty turn signal switch.
4. Faulty turn signal flasher. This same unit is used for the 4-way flashers (hazard lights).
5. Malfunctioning DRL (daylight running lamp) module.
6. Faulty emergency flasher switch. The front blinkers run through the contacts of the hazard switch twice. So this signal has to be good for the front blinkers to work.
7. Missing +12V feed or ground to the front turn lamp. They leave 12Volts on all the time for the running lamps and toggle the ground on/off when blinking.

The circuitry to the front blinker is more complicated than the signal to the back. The back goes through the fuse, the flasher, the hazard switch, the turn signal switch and then to the back lamps. The front also goes through 2 sets of contacts in the hazard switch and then to the DRL module where the 12V signal is inverted and the module cycles the ground connection on/off to cause a blinking effect.

In your case, the reason the left rear still blinks is because that circuit is intact and it runs directly off the output of the blinker So, something in the front blinker circuit is the problem, that's why the front lamp doesn't flash.

You could check the following:
1. Check the turn signal bulbs on the left side, front and back. You could swap the left and right bulbs if you can't tell the condition.
The fog lamps, license plate lamps, interior lamps, and headlamps are not involved in this circuit.
2. Cycle the hazard switch on/off about 40 times to clean the contacts a bit and see if the blinker gets better.
3. Use a 12V test light and verify that 12volts is getting to the left front turn lamp. Also verify that the ground to the lamp is good.
4. If the bulbs are good (both filaments), swap the left and right headlamp assembly which includes the blinker bulbs, sockets, etc and see if the problem stays on the left side. There's a plastic clip that pulls out so you can remove the whole headlamp assembly in 10 seconds.
5. Try pushing on the turn signal level a bit as you try it and see if it works - you might find the problem.
6. Try spraying some contact cleaner into the turn signal and hazard switches.
7. If the problem persists you may need to do some checking with an insulation piercing test light and find out where the signal is lost.

The turn signal indicator lamp in the dash is connected to the output of the turn signal switch. So if this blinks, that means the signal is getting through the turn signal switch and it's also ok at least as far as the DRL module input. The module itself is a 1x3x2" plastic box with 2 8 pin connectors. It's located above and to the left of the brake pedal. It's mounted on a slide and can easily be removed for testing. The module controls the automatic headlights and some other functions.

Note that the added load of some 12V test lights can trigger a fast blink condition when you are probing around. A low impedence volt meter may be of use here.
The purple wire on the flasher unit is the output. This serves as the input to the blinker switch.

Remember that the turn signal bulb also serves as running lights, so the blinker bulb will normally be on. When the DRL module alternates the ground connection to the lamp on and off then it serves as a blinker.
The back set is the opposite. With those, the ground is always present and it toggles +12Volts on/off.

Good Luck, I hope someone can use this info.

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