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Pacbrake exhaust brake need relay location

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Bryan Beamon:
Our exhaust brake is not working on our Cat C9 400hp.  In trouble shooting with Pacbrake they seem to think the solenoid is not getting the signal to activate the Pacbrake. Having difficulty locating the relay. I found the solenoid and found the ground wire but tracing the second wire to the relay has me stumped

Eric Maclean Co-Admin:
Bryan
On page #2 of the 2007 contessa wiring diagram found in coach assist library shows relay R18 as the exhaust brake relay.

It is to be noted that the exhaust brake is controlled through the engine ECM ( engine control module ) in conjunction with the TCM ( Transmission control module )
The exhaust brake relay ties into the brake light relay so the brake lights activate during exhaust brake operation.
If a following car can see brake lights under exhaust brake conditions the ECM is sending a signal to activate the exhaust brake.

Hope this helps
Eric

Bryan Beamon:
Eric, thank you. Do the Attached photos designate the relay you describe? I was confused by the description on the relay in my front service bay saying exhaust brake sol.

Bryan Beamon:
Second photo

Eric Maclean Co-Admin:
Bryan
Yes the relay is labeled exhaust brake solenoid: because it sends the signal to the air solenoid that operates the exhaust brake.

Eric

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