Headlights go dim randomly

JaySun

Original poster
Member
Feb 25, 2013
23
So that's about it randomly while driving my 2006 Chevy TB LS (4.2L I6) (or with the engine off and the lights on) the headlights will just go dim then bright, dim and then bright again in a cycle. I haven't noticed the high beams doing it and it wouldn't be that big of a deal but it's so low it's very noticeable I go from great visibility to not being able to see someone stand 2 feet in front of the vehicle. I've tried removing power from the system (resetting it), resetting the computer by holding the key for 30 secs after the TB is on, switching the relays that control the lo-beam lights, and replacing them with no luck. It occurs in both headlights at the same time, the volts gauge on the cluster doesn't move, and no other lights go dim.


Any advice or previous experience with this (and hopefully a fix) I'm willing to try about anything at this point :/?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
What's the frequency of the cycle? How many seconds on bright and how many on dim?

The headlights don't share a common ground, but the connection to the fusebox relay could be flaky.

Is this only when you have them on full bright at night? It's not the DRL that dims during the daytime?
 

JaySun

Original poster
Member
Feb 25, 2013
23
the roadie said:
What's the frequency of the cycle? How many seconds on bright and how many on dim?

The headlights don't share a common ground, but the connection to the fusebox relay could be flaky.

Is this only when you have them on full bright at night? It's not the DRL that dims during the daytime?

Honestly, it varies sometimes it'll be bright go dim for just a moment then go back to bright, sometimes it'll go dim and stay dim for a while, etc.

This is only the lo-beams happens during the day and night it happens at all times. I noticed there are separate relays for each low-beam headlight so I figured that wasn't an issue, considering they both go out and come in together but I suppose it can't be a connection from the headlight itself considering the high-beams don't have this issue...not sure
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
tiphat.gif
Welcome
tiphat.gif


In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/


There are separate fuses for each low beam, but just one relay, #46.
There are also separate fuses for each high-beam and one relay #43.
What you're describing sounds like a flaky relay #46.
Also, you have a 4.2 I6, not a 4.3.
 

JaySun

Original poster
Member
Feb 25, 2013
23
Wooluf1952 said:
tiphat.gif
Welcome
tiphat.gif


In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/


There are separate fuses for each low beam, but just one relay, #46.
There are also separate fuses for each high-beam and one relay #43.
What you're describing sounds like a flaky relay #46.
Also, you have a 4.2 I6, not a 4.3.

Thank you, and yes I read it in the welcome PM :biggrin:

So I switched relays and it seems ok around the block but the real test will be tomorrow so I'll let you guys know, thanks so much :smile:
 

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