Headlights Flickering/diming 2005 Trailblazer?

[Dave1]

My wife's 2005 Chevy Trailblazer has had an on going problem since new of the headlights flickering and dimming. We notice it when driving to work in the pre-dawn hours and it occurs most frequently when we let off the gas to slow down. It seems to be getting worse.

 

When the headlights dim, the dash gauge needle flicks around like there is an intermittent drop in charge voltage from 14+ to 13. We took the vehicle to our local Chev dealer and they could find no problem and offered no support.

 

I have read where some GM vehicles have had this problem but I could not find an exact resolution. This vehicle now has 35,500 miles on it and the waranty is about to expire so if this can be corrected via waranty, we need to do it quick.

 

Any help and info to resolve this problem would be appreciated.

 

Thanks, Dave

[jhm]

My wife's 2005 Chevy Trailblazer has had an on going problem since new of the headlights flickering and dimming. We notice it when driving to work in the pre-dawn hours and it occurs most frequently when we let off the gas to slow down. It seems to be getting worse.

 

When the headlights dim, the dash gauge needle flicks around like there is an intermittent drop in charge voltage from 14+ to 13. We took the vehicle to our local Chev dealer and they could find no problem and offered no support.

 

I have read where some GM vehicles have had this problem but I could not find an exact resolution. This vehicle now has 35,500 miles on it and the waranty is about to expire so if this can be corrected via waranty, we need to do it quick.

 

Any help and info to resolve this problem would be appreciated.

 

Thanks, Dave

Sounds like your alternator has some bad diodes. Check with some place like Autozone, they will check it for free.

[Rolling]

I have seen the wires inside the headlamps on the the trailblazers short causing the headlamps to dim and flicker, I dunno if this would cause the voltage to spike or not...

Pretty easy to check, pop one of the 3" caps off the back of the headlamp housing and look at the insulation on the wires. If you have aftermarket ( brighter or blue or high draw bulbs) this may cause the problem to happen faster. If this actually is your problem. Good luck!

[Wingnut]

I'd say to take it in until they fix it...But I know better. Mine did the same thing.

 

If you REALLY want it to go away, upgrad the "big 3" and get a beefier alternator.

[Dave1]

What do you mean "upgrade the big 3"???

 

I have read where others had the problem and it was thought to be some kind of defective connector or similar on part of the wiring harness that plugs into the alternator.

 

I don't understand why, if the alternator is slightly under sized, it would cause the headlight flickering, meter fluxuations, etc.

 

Dave

[no bull]

Had sam e problem with my yukon....beleive it or not it was just a lose battery connection!

[TxTruckMan]

I had the same problem with my '96 Z71. It turned out to be the alternator. O'Reilly's checked it out and said it was still good, but I got a new one anyway (I had a lifetime warrnty on the previous one). Problem fixed.

[atboley]

Most of the time, things like this can just be normal, unless the problem is very severe. the problem could

also be the idle dropping to low when comming to stops and not spining the alternator fast enough to

keep up enough charging voltage. trailblazers throttlebodys are very sensitive to build up of dirt,

get some throtlebody cleaner and clean and scrub your throttlebody real good, or take it somwhere

and have a throttlebody service done. once that is done the idle shouldnt drop to low when it

comes to idle with alot of load because it wont be suffocated for air...

[atboley]

Most of the time, things like this can just be normal, unless the problem is very severe. the problem could

also be the idle dropping to low when comming to stops and not spining the alternator fast enough to

keep up enough charging voltage. trailblazers throttlebodys are very sensitive to build up of dirt,

get some throtlebody cleaner and clean and scrub your throttlebody real good, or take it somwhere

and have a throttlebody service done. once that is done the idle shouldnt drop to low when it

comes to idle with alot of load because it wont be suffocated for air...

 

also just remember to check the basics like battery connection, take them both off and check for corrosion,

if the dealer cant find anything after a few ryes and you really cant stand it, you could put a higher amp alternator

on it, but i doubt the dealer would do that for you under warranty