Test A (Code 39): Compressor Relay Circuit
NOTE:
For TEST "A" pin connector test locations See Fig 1.
- Horn circuit and air suspension circuit use same type of relay. Depress horn pad to ensure horn is working. Remove horn relay, located in fuse/relay box directly behind battery, and install in place of compressor relay. Repeat SERVICE BAY DIAGNOSTICS under TESTING & DIAGNOSIS. If Code 39 is displayed, install relays in original position and go to next step. If Code 39 is not displayed, install horn relay in original position. Replace compressor relay. Repeat SERVICE BAY DIAGNOSTICS under TESTING & DIAGNOSIS.
- Turn air suspension switch off. Disconnect control module connectors. Remove compressor relay from fuse/relay box located in engine compartment, behind battery. Turn air suspension switch on. Measure voltage between pins No. 23 and No. 6 on harness side of module connectors.
- Zero volts should be present. If zero volts is present, replace control module. Repeat SERVICE BAY DIAGNOSTICS under TESTING & DIAGNOSIS. If 12 volts is present, repair short to battery in circuit No. 420 (Dark Blue/Yellow wire). Repeat SERVICE BAY DIAGNOSTICS under TESTING & DIAGNOSIS.