| Subject: | Electronic Brake Control Module (EBCM) Replacement | 
| Models: | 1990-2000 Chevrolet and GMC Medium Duty Conventional, T-Series Tilt Cab and B7 School Bus Models | 
| With 7.4L Engine (VINs B, D -- RPOs L21, LP4) or 7.2L Caterpillar® Diesel Engine (VIN C -- RPO LG5) and Hydraulic ABS Brakes | 
| Built Prior to March 7, 2000 and the Following VIN Breakpoints: | 
Plant  | Make  | VIN Breakpoint  | 
|---|---|---|
Janesville  | Chevrolet  | YJ517376  | 
Janesville  | GMC  | XJ905114  | 
This bulletin is being issued to inform technicians that when replacing the electronic brake control module (EBCM) on the above listed vehicles with the new EBCM P/N 12477736, the red (primary) brake light may illuminate.
In order to avoid a misdiagnosis of the service EBCM and to address the false illumination of the brake light, please perform the following steps:
For vehicles repaired under warranty, use:
Labor Operation  | Description  | Labor Time  | 
|---|---|---|
N6600  | Wiring and/or Connector, Brake System/Traction Control - Repair  | 0.2 hr  |