Lights Flickering

[bq9661]

On my 03 Denali, the headlights and interior lights flicker really bad at any given time. There is no rhyme or reason on when they flicker (like bumpy roads), but I know it drives me and the car in front of me nuts. Sometimes during these flickers, I can hear the whoosh noise coming from the brake pedal as if the traction control is kicking in and slighty feel some brake being applied even though my right foot is on the gas. Of course during the day I can't tell if this flickering is happening, but I don't hear/feel the traction control kicking in. Any ideas before I head to the shop?

[00Silverado4x4]

Have you checked all your connections for condition and security? Just a left field suggestion but maybe you have a corroded/loose battery wire(s).

[joefrog]

Question, what does this bulletin say?

"Review bulletin 02-06-03-008A - Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged"

 

My 2003 Denali was purchased in July with about 130,000 miles on it. The lights -- ALL of the lights -- pulse. The clock, the radio, the headlights... They don't go out, but they do pulse rhythmically. Very noticeable at night and quite annoying.

 

I'd love to fix this -- but what bulletin info is in the one referenced?

 

Thanks,

Joefrog

[joefrog]

Question, what does this bulletin say?

"Review bulletin 02-06-03-008A - Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged"

 

My 2003 Denali was purchased in July with about 130,000 miles on it. The lights -- ALL of the lights -- pulse. The clock, the radio, the headlights... They don't go out, but they do pulse rhythmically. Very noticeable at night and quite annoying.

 

I'd love to fix this -- but what bulletin info is in the one referenced?

 

Thanks,

Joefrog

 

 

Oh, and you can actually watch the volt meter fluctuate up and down. The alternator was tested as being just fine.

[bq9661]

Thanks for the above info! I should have clarified that this seems to only happen when under way... both just cruising and accelerating. I have yet had this happen while sitting idle.

[GM-Tech]

  I have yet had this happen while sitting idle.

 

<{POST_SNAPBACK}>

 

 

 

 

This is when it should be most noticeable if it's the problem listed in the TSB up above.

[bobcat5544]

Document ID# 1750221

2003 GMC Truck Yukon Denali

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Subject: IPC, Interior Lights and/or Headlamps Flicker - keywords battery courtesy electrical fluctuation generator head intermittent lamp light #PIT3170E - (01/11/2006)

 

Models: 1999-2005 All Cadillac Full Size Utilities

1999-2005 All Chevrolet Full Size Trucks and Utilities

1999-2004 Chevrolet Blazer, S-10

1999-2005 All GMC Full Size Trucks and Utilities

1999-2004 GMC Envoy Classic, Jimmy, Sonoma

1999-2001 Oldsmobile Bravada

Without Regulated Voltage Control

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Customers may have comments of a flickering light condition in the IPC, interior lamps or headlights. This condition is most likely to be noticed when the engine RPM is low and when high electrical load requirements are in place on the generator.

 

Recommendation/Instructions:

Important: Review bulletin 02-06-03-008A - Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, before proceeding with this PI.

 

Disconnect the negative battery cable from the battery/batteries.

Slide the protective boot on the generator BAT terminal aside and remove the retainer and wire cable from the BAT terminal.

Unplug the generator 4-cavity terminal from the top of the generator.

Inspect cavity D on the generator connector for a red cavity plug. If a red cavity plug is present, it is not necessary to replace the generator connector. Remove the CPA and save. Remove the red cavity plug and continue with step 9. If a red cavity plug is NOT present, continue with the next step.

Remove and save the orange Weatherpack seal and CPA from the 4-way connector.

Using the proper terminal removal tool, remove the two or three wires from the 4-way connector. On vehicles without Supplemental Brake Assist (SBA), install a red cavity plug, P/N 12059168, into cavity "A" of the new 4-way connector, P/N 12186568. On some 2003 and 2004 model year vehicles with SBA, install the dark blue (Circuit 5668) wire of the vehicle wiring harness into cavity "A" of the new 4-way connector.

Depending on the vehicles model and year, install the brown wire (Circuit 25) or red wire (Circuit 225) of the vehicles wiring harness into cavity "B" of the new 4-way connector.

Install the gray (Circuit 23) wire of the vehicle wiring harness into cavity "C" of the new 4-way connector.

Obtain a piece of 0.80 mm/18GA black wire, 254 mm (8 in) long.

Install a red terminal seal, P/N 12048086, and terminal, P/N 12048074, (crimp and solder) on one end of the new black wire.

Install the new black wire into cavity "D" of the new 4-way connector.

Reinstall the connector seal and CPA, from the original connector, to the new connector.

Plug the 4-way connector into the generator.

Route the black wire to the generator BAT terminal, sliding the wire into the small end to the output terminal boot, along side the generator output wire.

Obtain a ring terminal from the terminal kit (J-38125-D) that is the same diameter as the positive post of the generator. Crimp and solder the ring terminal from the terminal kit (J-38125-D) on to the open end of the new black wire.

Place the generator output wire and the new black wire onto the generator BAT terminal and install the retainer.

Connect the negative battery cable.

Note: This modification will not work if the vehicle is utilizing the new "Regulated Voltage Control" system. This is new feature on some full-size trucks and utilities for the 2005 model year. Please inspect the vehicle prior to performing this modification.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[GM-Tech]

Note that the flickering condition fixed by the above TSB is very slight. It's almost undetectable unless you're paying attention. So if yours is "bad" as you say, this may not help but it's worth a shot.