IA14 Checking Wiring Harness (Circuit 175)
^ Using a voltmeter, connect positive lead to Circuit 175 of the air compressor relay's wiring harness connector and negative lead to Circuit 430B.
^ Is voltage reading greater than 10 volts?
YES -- GO to IA15.
NO -- SERVICE open or short in circuit. There should always be battery voltage on this circuit. REPEAT Service Bay Diagnostics after service is made.