2003 Chevrolet Suburban



July, 22, 2011 AT 5:15 PM

I have a 2003 Chevy Suburban Z71(103k miles) and there is a flicker in the interior lights and will have the headlights go out for a split second when first starting it and shifting into drive and take accelarating to take off. I also get the interior lights to go off for a split second when shifting from park to drive and drive to park. I had the vehicle in at a GMC Dealer and they tested the alternator, light dimmer switch and checked grounds and can't find anything wrong even though the condition appears for them. I also had the alternator tested numeroud times at autozone and advanced auto parts and it always test good. Also has a newer battery, 7 months old, that tests good as well. If I drive out of the city i can notice the flicker in my headlights while driving. What could be causing this?

The computer field generation duty cycle circuit was checked and the condition was not present and no defects were found in the circuit. I found this Pre service bulletin online but the service advisor is hesitant to do anything with it becuase it is old? anyone heard of this or know if it works or have any other ideas?

Here is what I found Online but it is old:

IPC Interior and/or Headlamps Flicker - keywords battery courtesy electrical fluctuation generator head intermittent lamp light #PIT3170D - (Jul 20, 2005)

1999-2005 All Cadillac Full Size Utilities
Without Regulated Voltage Control

1999-2005 All Chevrolet Full Size Trucks and Utilities

Without Regulated Voltage Control

1999-2004 Chevrolet Blazer, S-10

1999-2005 All GMC Full Size Trucks and Utilities

Without Regulated Voltage Control

1999-2004 GMC Envoy Classic, Jimmy, Sonoma

1999-2001 Oldsmobile Bravada

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


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.


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.
Install the brown (Circuit 25) wire of the vehicle 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 bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

? Copyright General Motors Corporation. All Rights Reserved. http://www.chevytalk.org/fusionbb/showtopic.php?tid/119594/


4 Answers



July, 22, 2011 AT 6:08 PM

It sure looks to me like it pertains to your vehicle: 1999-2005 All Chevrolet Full Size Trucks and Utilities
I'd say take it to a different dealer and tell them to fix it.



July, 22, 2011 AT 6:18 PM

You got a bad ground in the engine compartment. Key off the headlight flicker. Youll need a multi meter to start testing grounds and connectors.



July, 22, 2011 AT 6:51 PM

The GMC Dealer ran tests and could not find a ground issue.



July, 22, 2011 AT 7:37 PM

Thats just it they cant find it. Check for bullitens. You need a diagram and ground locations and check them all.

Please login or register to post a reply.

Alternator Replacement Ford Super Duty
Alternator testing done right
Alternator Replacement Chevrolet Silverado
Serpentine Belt Replacement Chrysler