Test Point 1

Test Point 1

Data lead, air conditioner - PCM

Open circuit/short to ground
Short to B+
Signal disturbance

Fault code 20

Open circuit/short to ground
1. Pull off plug II on the display and operator control unit.
2. Pull off plug C on the heater / A/C control unit.
3. Check lead from plug II pin 15 to plug C 12 for continuity and short to ground.

NOTE: The lead is routed via the 10-pole plug connection on the heater/ A/C unit.

Short to B+
1. Pull off plug II on the display and operator control unit.
2. Pull off plug C on the heater / A/C control unit.
3. Check lead from plug II pin 15 to plug C 12 for short to B+.

Signal disturbance
Check wiring harness for short with other leads.