EF1 Star Code 45 Short In Air Compressor Relay Circuit

^ The air suspension control module has detected a short in the circuit used to activate the air compressor relay. There are four possible causes of this short which are listed below:

^ B+ power supply circuit is shorted to ground.

^ Vehicle wiring harness has B+ power supply circuit and ground return circuit in wrong location.

^ Air compressor relay is inoperative.

^ Air suspension control module is inoperative.

^ The air compressor relay has a diode in it. When current is applied in the reverse direction this diode will act like a short. Because all ohmmeters do not have the same positive and negative polarity, the following test procedures are being used to locate the cause of the short.

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