What I’ve done so far:
- New OEM AMK compressor installed ~1 year ago (plus reservoir tank, center valve block, and front valve block replaced at the same time).
- Replaced fuses FL10, F26, F3, F35
- Replaced relay (R7)
- Battery disconnect (15 min) – no change.
- Cleared code multiple times with scan tool – code comes back instantly, compressor never even attempts to start.
- Scan tool shows:
- Compressor relay = OFF (never commanded ON).
- Compressor voltage = 0 V.
- Pressure sensor Vref = 4.9 V (so ECU is powering it).
- Gallery pressure stuck at ~12.8 psi.
- Rocker panel under passenger door had water intrusion (sunroof tubes duh); loom dried but still suspicious
- Current suspicion:
- ECU is not seeing a valid signal from the reservoir pressure sensor (inside reservoir valve block).
- Either the sensor itself is bad OR the signal wire is open/corroded in the passenger rocker loom.
- Next step I’m considering:
- Running a continuity test from the pressure sensor signal wire at the reservoir valve block back to the suspension ECU behind the glove box (long jumper wire).
- Question for the community:
Does this sound like the right next diagnostic step? Has anyone else confirmed a rocker-loom wire failure (open or corroded) as the root cause of a C1131-92 with a non-running compressor?
