EF3 Check Resistance Between Pin 35 and 40

^ Disconnect air compressor relay from vehicle wiring harness.

^ Using an analog ohmmeter, connect one lead to air compressor relay vehicle wiring harness connector Circuit 430B and other to a known good chassis ground.

^ Is ohmmeter reading less than 2 ohms?

YES -- REPLACE air compressor relay and REPEAT Service Bay Diagnostics. Reading and Clearing Diagnostic Trouble Codes

NO -- SERVICE short in wiring harness Circuit 420/430G. REPEAT Service Bay Diagnostics. Reading and Clearing Diagnostic Trouble Codes