Electrical Systems Reference

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Note: Content within this and other topics in this section are for CAFCNA Members only. It is NOT for commercial use in ANY form, by anyone. (Except GM)

Note: Posts in this topic are used primarily for reference, than that of instruction or information.

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2002 UBEC Component Location

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2003~2006 UBEC Component Location

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2003+ Trailer Wiring Diagram

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Trailer Brakes Applied When Headlights/Park Lamps are On, Brake Controller Illumination (Modify Brake Controller Wiring Harness) #02-05-22-004B - (Oct 22, 2002)

2002-2003 Cadillac Escalade, Escalade EXT

1999-2003 Chevrolet Silverado

2000-2003 Chevrolet Suburban, Tahoe

2002-2003 Chevrolet Avalanche

1999-2003 GMC Sierra

2000-2003 GMC Yukon, Yukon XL

2003 HUMMER H2

This bulletin is being revised to add additional model years and information. Please discard Corporate Bulletin Number 02-05-22-004A (Section 05 -- Brakes).

Condition

Some customers may comment that when the headlamps or park lamps are on, the brakes on the trailer are always applied, or that the back lighting for the trailer brake controller only illuminates when the brakes are applied.

Cause

The cause of this condition may be due to wiring changes within the vehicle electrical system for the 2003 model year.

Correction



Inspect the brake controller wiring harness jumper that is plugged into the vehicle relay block-body. The relay block-body is located under the left side of the instrument panel near the left kick panel, behind a plastic cover.

The 1999 though early 2003 wiring harness jumper that plugs into the relay block will have a reddish/brown 6-way connector and a tag with the last four digits of the wiring harness part number. Second design 2003 may have a white plastic connector with part number 5418 as well.

    * The 1999 jumper is/was P/N 12171982 with a pink/purple tag identifier of 1982. This number has been superseded to 15366255, with a pink/purple tag identifier of 6255.
    * The 2000 jumper harness is P/N 15366255. The pink/purple tag identifier is 6255.
    * The 2001-2002 jumper is P/N 15086884. The orange tag identifier is 6884.
    * The 2003 jumper is P/N 15085418. The orange tag identifier is 5418.

When transferring the brake controller with the wiring jumper attached from a 2001-2002 vehicle to a 2003 vehicle, a change to the jumper harness connector must be performed.



The following information is for the 1999-2002 wiring harnesses.



To modify a 12171982, 15366255 or 15086884 harness for use in a 2003 vehicle, switch the wires in cavities "A" and "D".

To modify a 15085418 harness for use in a 1999-2002 vehicle (see model list at the front of this bulletin for applicable models), switch the wires in cavities "A" and "D".

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GM Document ID# 1173350

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2002 Original Trailer Wiring Diagram

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02 Cargo Lamp & Switch Wiring Diagram.
Driver Door Wedge Switch Diagram.

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2003 Cargo Lamps Wiring.

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BCM Power, Ground & DATA

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Sunroof Power and motor control.

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Relay Block I/P Layout

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Ignition Switch Start & Run Wiring 03+ to date.

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A Zipped file of the electrical connector end views and charts, is located HERE. The format used is a later version of Zip which is compatible with the long file names. Use a late version of 7-Zip, or compatible extractor.

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03+ DRL Wiring Diagram

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Seat Harness Connector & Wire ID - 03+ (to Date)