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Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 Vortec 4.2L I-6 Engine and Drivetrain > OEM Issues

OEM Issues Original Equipment Repairs and/or Problems

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  #1  
Old 03-12-2007, 01:07 PM
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michiganTB michiganTB is offline
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headlights dimming

So last night i was on my way home, i had been driving for about 15 minutes on surface street sthen hit the freeway, when i ws at my exit another 15 minutes away, the headlights started dimming whenever i would hit the breaks. the didnt go out the would just pulse, it was like they were being drained of power and then would get it back. the dash lights were also dimming and the voltmeter was dropping aswell. it never dropped below ~12 or so and i havent driven yet today. Anyone have any ideas they would be appreciated.
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  #2  
Old 03-12-2007, 01:27 PM
mgawlik1 mgawlik1 is offline
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If you were losing power while driving, there very well could be an issue with your alternator. I had that happen once to me too, eventually it got too low to even drive. I would definatley have it checked out along with the battery too.
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  #3  
Old 03-12-2007, 01:31 PM
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  #4  
Old 03-12-2007, 10:19 PM
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may just check to see if you have a good ground still sometimes the y loosen up and cause similar problems.
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  #5  
Old 04-03-2007, 10:12 AM
briant73 briant73 is offline
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I have noticed my headlights dimming/flickering at night also. I usually notice this at highway speeds when I let off the gas, the lights seem to flicker/dim a lot.

I am under warranty but if it's a ground cable loose I can check that but where are the grounds on the Trailblazer?
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Old 04-03-2007, 10:31 AM
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Blazernut Blazernut is offline
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Quote:
Originally Posted by briant73 View Post
I have noticed my headlights dimming/flickering at night also. I usually notice this at highway speeds when I let off the gas, the lights seem to flicker/dim a lot.

I am under warranty but if it's a ground cable loose I can check that but where are the grounds on the Trailblazer?
Follow the negative Battery terminal lead to it's ground point. Check and clean both ends.

Look for the Engine block to frame ground then clean and re-tighten both ends. Also check the Alternator connections for tightness.

B.
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  #7  
Old 04-03-2007, 10:26 PM
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To the owners with the dimming/pulsing lights while coasting at speed, did this happen for you while it is wet out? My 2005 LS has done this, but only in the rain. I've yet to find the culpret connection.

Joel
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Old 04-03-2007, 10:32 PM
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michiganTB michiganTB is offline
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for me it didnt happen in rain and it has only happened a few times since. the different times have been as follows

1- highway speed let off gas to exit and as i came up the ramp th headlights and dash lights dimmed and the voltmeter dropped to just under 14

2- same thing but driving around city doing no more than 50


it seems like it only does it when the car is decelerating(sp) but there is no brake applied. i havent even checked any of the wires because it has been such an infrequent problem but i think i may check them tomorrow.

Whats the worst scenario that this could be?
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  #9  
Old 04-03-2007, 10:38 PM
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Originally Posted by michiganTB View Post
..it only does it when the car is decelerating(sp) but there is no brake applied.
Yep, same EXACT thing here. The dash lights & headlights pulse big time, but the engine never so much as stumbled or varied in RPM's. I havent gotten it to replicate in a few weeks. I hate those problems!

Joel
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  #10  
Old 04-04-2007, 09:47 AM
briant73 briant73 is offline
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My problem is very similar, highway speeds, let off gas, watch the lights flicker.

I disconnected the battery last night, checked all the ground connections I could find in the engine bay, reconnected the battery (have your keys nearby when reattaching the negative since mine set off the panic alarm but simple keypress on the fob corrected).

Drove on the highway let off gas and watched for it and no problem seen, but the problem is intermittent. I wonder if there is a TSB for it?

Quote:
Originally Posted by MTPockets View Post
Yep, same EXACT thing here. The dash lights & headlights pulse big time, but the engine never so much as stumbled or varied in RPM's. I havent gotten it to replicate in a few weeks. I hate those problems!

Joel
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