For 1990-2009 cars

# Radio Inoperative Except in RAP and Other Electrical Concerns - A/C AC accumulator audio BCM bilevel cassette CD compressor cool coolant duct DTC ECC eject electrical equalizer fuse ground HVAC

Subject: | Radio Inoperative Except in Rap and Other Electrical Concerns

Models: | .

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

### Condition/Concern:

Radio inoperative with key on, auto door lock feature disabled, a/c compressor does not engage and DTC U1255 stored in the radio. Radio may work in rap or accessory until the door is opened.

### Recommendation/Instructions:

Cause: Clamp 15A, fuse #10, 10 amp fuse blown to the BCM/PZM, terminal A11. This fuse is normally powered in run and not during cranking. When this fuse is blown, the BCM acts as though it is in the crank mode with the key on. The BCM turns the radio off via CLASS 2 and inhibits auto door lock operation. The HVAC control head inhibits a/c compressor operation.

CORRECTION:

1. Replace the 10 amp #10 fuse.
2. Check the heater water pump located at the right wheel well area for a leak. Also, check the auxiliary pump located on the left side of the radiator support for a leak. If either pump is leaking, coolant may be dripping onto a connector for this fused circuit which may cause a short to ground condition.
3. If both pumps are okay, install in-line fuses rated less then the fuse in question for each component affected to isolate the failed circuit.

Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

### Models:

(97, 98, 99, 00, 01 Cadillac Catera)