Operation CHARM: Car repair manuals for everyone.

Constant Control Relay Module

The constant control relay module uses a combination of relays and solid state switches to control the following systems:
- engine cooling fan
- GA/C clutch
- fuel pump
- powertrain control module power

The powertrain control module can interrupt A/C compressor operation through the constant control relay module under the following conditions:
- during engine start-up
- Wide Open Throttle (WOT)
- low engine idle conditions
- excessively high engine temperatures