Headlights Flicker

Tcme64 · November 6, 2014

I have a 2010 Tahoe with 84,000 miles on it. About a month ago I noticed at night my headlights would flicker almost like a strobe light. I put 2 new bulbs in and that did not fix it. My local dealership has had it a long time. They put a new alternator in it and that did not fix it. The Tech has been driving it home at night and he sees the problem also. They do not know what is wrong. I have read that this is a problem and nothing can be done to fix it. Doubt if that is true. Any help would be appreciated

SouthernSilveradoGuy85 · November 6, 2014

Bad wire somewhere, may just be loose or damaged. One of the reasons I hate electrical work unless it's basic. Take it to good shop or if you take it to the dealer make sure they get a GM certified tech to work on it. I had a wiring issue on my old 98 where the headlights and taillights wouldn't come on. The place I took it to the owner luckily had a buddy that works at the Chevy dealer here in town and they got it fixed. It was a bad wire somewhere. I can't remember where though.

Tcme64 · November 6, 2014

Bad wire somewhere, may just be loose or damaged. One of the reasons I hate electrical work unless it's basic. Take it to good shop or if you take it to the dealer make sure they get a GM certified tech to work on it. I had a wiring issue on my old 98 where the headlights and taillights wouldn't come on. The place I took it to the owner luckily had a buddy that works at the Chevy dealer here in town and they got it fixed. It was a bad wire somewhere. I can't remember where though.

Thanks. It is at a GM dealer. They can't find any wiring issues. They are waiting for GM Tech support for help

SouthernSilveradoGuy85 · November 6, 2014

Thanks. It is at a GM dealer. They can't find any wiring issues. They are waiting for GM Tech support for help

When I said GM certified tech I didn't mean just anyone in the service department, they have GM certified techs that are required for some recalls and work. Think of a GM certified tech as an ASE certified tech at any other shop and that's specific to GM vehicles.

Tcme64 · November 6, 2014

When I said GM certified tech I didn't mean just anyone in the service department, they have GM certified techs that are required for some recalls and work. Think of a GM certified tech as an ASE certified tech at any other shop and that's specific to GM vehicles.

Southern. They tell me this is one of their best techs and he is certified. I think most or all of them are. Even the head of service department who has been there forever is on top of it. They are stumped. I just hope what I read in some other forums is not true. They say " This is normal" or " Nothing can be done. I doubt this is the case considering I bought it new in 2010 and it just started. Even the dome lights flicker. Makes me almost sick to stomach while driving at night. Like a low power strobe light... LOL

ifixedit · November 6, 2014

It's a sign of a connection somewhere that has degraded over time and is not making a good clean contact and is now likely being affected by temp changes, humidity changes and so on. I recently had the lights flickering and other more serious issues (that I won't get into here) that I think I have finally resolved.

Tell them to disconnect ALL the plugs to the BCM (body control module) under the dash, pack dielectric grease in all the plugs, reconnect, drive and then see what happens. If there's one thing I've learned, GM seems to have a hell of a time coming up with plugs and connections that over time will continue to pass a strong uninterrupted current.

If that doesn't help I'd be taking a look at the headlight switch and the connections to it, give them the dielectric grease treatment as well.

Tcme64 · November 7, 2014

It's a sign of a connection somewhere that has degraded over time and is not making a good clean contact and is now likely being affected by temp changes, humidity changes and so on. I recently had the lights flickering and other more serious issues (that I won't get into here) that I think I have finally resolved.

Tell them to disconnect ALL the plugs to the BCM (body control module) under the dash, pack dielectric grease in all the plugs, reconnect, drive and then see what happens. If there's one thing I've learned, GM seems to have a hell of a time coming up with plugs and connections that over time will continue to pass a strong uninterrupted current.

If that doesn't help I'd be taking a look at the headlight switch and the connections to it, give them the dielectric grease treatment as well.

Thanks a bunch. I will call them this AM and discuss this with them. They are sure looking for help. Electrical issues can big a real pain

Tcme64 · November 7, 2014

OK. They said they have it fixed. The battery??????????? It is only 8 months old and they said it tested fine but they put a new one in and the flickerin stopped. Kind of strange

Duelin · November 7, 2014

Have you ever had any aftermarket accessories installed?

ifixedit · November 7, 2014

Also a question: Have you ever noticed things like the door locks when using the FOB acting weird, not working correctly, interior or entry lights not doing what they should and so on?

The battery? Now that's interesting, you'd think they would have caught that right away, but I supposed anything is possible, could have been as simple as the battery connections just weren't that good. If it was the original AC Delco battery then it was about due to be replaced anyways, they seem to die right on time between 4 and 5 years almost like they have a timer built into them! As long as the lights now work correctly that's what counts. In my situation over time the plugs to the BCM were evidently not always passing a strong signal and was intermittent at times causing all kinds of problems. You go down a bumpy washboard gravel road and things get jarred around, one day it's fine and the next the connections could be questionable causing problems like you describe. Your truck is only 4 years old but could be suffering from some of this already. I'd still have them disconnect all the BCM plugs and give them the dielectric grease treatment just for good measure, it sure won't hurt anything.

Tcme64 · November 7, 2014

Also a question: Have you ever noticed things like the door locks when using the FOB acting weird, not working correctly, interior or entry lights not doing what they should and so on?

The battery? Now that's interesting, you'd think they would have caught that right away, but I supposed anything is possible, could have been as simple as the battery connections just weren't that good. If it was the original AC Delco battery then it was about due to be replaced anyways, they seem to die right on time between 4 and 5 years almost like they have a timer built into them! As long as the lights now work correctly that's what counts. In my situation over time the plugs to the BCM were evidently not always passing a strong signal and was intermittent at times causing all kinds of problems. You go down a bumpy washboard gravel road and things get jarred around, one day it's fine and the next the connections could be questionable causing problems like you describe. Your truck is only 4 years old but could be suffering from some of this already. I'd still have them disconnect all the BCM plugs and give them the dielectric grease treatment just for good measure, it sure won't hurt anything.

No it is a DEKA and is 8 months old. The dome lights still flicker

ifixedit · November 7, 2014

If that's the case I would definitely take a look at the plugs to the BCM, the interior lights are one of the things controlled by the BCM. Tell them to amuse you and just disconnect all the plugs to it (also with the battery disconnected first), pack the plugs with dielectric grease, reconnect the plugs to the BCM, then reconnect the battery and see what happens. I'd also be taking a close look at the headlight / dash light dimmer / dome light switch or it's connections.