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View Full Version : Help, Flasher/Brake Switch Woes…



TurboDiverArt
11-27-2007, 18:30
Hi All,

Strange thing I noticed tonight with my Suburban. I was turning onto the highway with my turn signal on and when I got onto the highway and turned my signal off I could hear the flasher still blinking. The turn signal lights were not on but I could hear the flasher still making the blinking sound. It stayed this way and eventually got to a slower blink rate and went away. While on the highway occasionally when I changed lanes the flasher would stay on. The turn signal lights would go off as they should but I could still hear the flasher blinking. If I quickly put the turn signal on and then off I could sometimes get it to stop. When I turned into my driveway I put the turn signal on to see if I could reproduce the problem and it did. I got under the dash and was able to confirm it was the flasher (GM part number 11516051). I could definitely feel with my finger that the flasher was making the sound. I tried tapping on the flasher but it kept blinking. I pulled out the flasher and the sound stopped (duh). To my surprise when I put it back in it kept right on making the sound. I tried turning on and off the turn signal as well as the hazards but the flasher kept on blinking. I turned off the truck and the flasher stopped. When I turned the key to the run position the flasher started again. I tried it a few times but it always goes back on when I turn on the key. If I touch the brake pedal the flasher stops. Please tell me its not that damn brake switch again. This would be the third time I’ve replaced it in less than 3 years!

The fact that the blinking doesn’t stop when the flasher is pulled and put back in tells me that it’s not the flasher itself but something telling the flasher to turn on. In addition, the fact that it stops when the brake is depressed tells me that it’s not the turn signal since the turn signal normally continues to work when the brake is applied. I believe the hazards stop when the brake is applied. To me it seems to point to that damn brake switch!

Maybe I’ll try a GM one if I can find the GM part number. I’ve already tried one from Advance Auto and one from Auto Zone and each seems to have lasted about a year and a half…

Art.

DmaxMaverick
11-27-2007, 18:46
Hazard flasher, perhaps? Some models have a flasher separate from the turn signal. Not sure about 1999, but previous models have a history of a failing hazard/turn switch cluster, but I've never heard of your condition. I would have blamed it on the golf ball in the glove box.

TurboDiverArt
11-28-2007, 03:39
Hazard flasher, perhaps? Some models have a flasher separate from the turn signal. Not sure about 1999, but previous models have a history of a failing hazard/turn switch cluster, but I've never heard of your condition. I would have blamed it on the golf ball in the glove box.

Where is the hazard flasher? I believe in the fuse block I have 3 flasher type devices. The one is the flasher that I described above and it's square. The other is a smaller rectangular one that is to the left of the flasher. The other is a very large rectangular one that is above the flasher.

Art.

DmaxMaverick
11-28-2007, 09:40
I'm not sure about the 99. I'd have to see a diagram, or get under the dash. Plugin boxes there could be flashers, circuit breakers or relays. You should be able to tell by the markings on them. You can also tell by turning on the turn signal and hazard separate, then hear/feel the box to know which one is clicking. If the turn signal flasher is clicking, the signal lamps should be flashing. They are load dependent (unless it has a trailering circuit, like the GMT-800 series), so It's hard to believe it could be flashing w/o something on the end of the circuit, like a lamp, sounding off.

JohnC
11-28-2007, 16:02
WAG---

Since turning the brake lights on changes the behavoir, I'd look at the grounds in the tail lights...

DA BIG ONE
11-28-2007, 21:20
I had to change out my tail light assemblies because of melted and burned bulb sockets, seems to be an issue on 1999 burbs.

DmaxMaverick
11-28-2007, 21:31
Good point, and certainly a possibility. I have one assembly left off the '95 GMC Sierra I've been parting out. I don't remember which side, but I can check, if you need one.

TurboDiverArt
11-29-2007, 04:19
I had to change out my tail light assemblies because of melted and burned bulb sockets, seems to be an issue on 1999 burbs.

Just pull the tail light assemblies and check the socket wiring, that's it? The only modification I've done to the wiring back there is for my auxiliary back-up lights. I tapped off the backup light wire and ran it to my relay that powers the aux lights so there is no load on it. There should not be any additional load on the stock wiring.

I'll have to pull them and tale a look tonight.

Art.

03Duramax
05-03-2008, 15:24
Hey Art, I have some ice and meet for you when you get a chance stop by.

baadgn
05-04-2008, 09:17
Did you get it fixed yet? :confused: ;)