Chart B-8 No Communication to IPC W/Only Radio Functions

Chart B-8 - No Communication To IPC With Only Radio Functions:

Wiring Diagram for Charts B-7 & B-8:

CHART B-8 - NO COMMUNICATION TO IPC W/ONLY RADIO FUNCTIONS

Circuit Description:

Because the CRT can only display Radio functions and the IPC cannot communicate with the BCM as the speedometer is blank, the whole system is down, or the IPC has lost its ground which stops all communication. The BCM wakes-up (turns on) everything else, however, we know the BCM can function as it turned the courtesy lights on. This could mean the BCM is not waking-up when the ignition is on.


Test Description:

1. Since the BCM uses the Ignition # 3 circuit to know when it is time to turn on, first check the 10A fuse.

2. If the fuse was blown, use another fuse to determine if the short is intermittent before isolating fault.

3. If the fuse was not blown, check voltage at the BCM with a test light. If the test light does not light, this circuit is open.


4. If the test light lights, remove the IPC to determine if the fault is loss of IPC grounds, or faulty BCM connector, or BCM. If the problem was loss of ground to IPC, when the IPC is removed, the CRT will work.


5. Verifying the integrity of the ground circuit at the IPC will determine if the circuit is open, or if the problem is a faulty IPC connector or IPC.