PacBreak PRXB/Switch-Pac C18042

[WStrmiska]

Need some information from you guys or gals that have installed your own PacBrake with the optional Switch-Pac that you mount on the shifter instead of the panel. My question is, how does the switch activate the exhaust brake butter fly. Thier is no wires leading to the air compressor from the switch. The switch wires, the black wire is a ground and the white wire goes to Pin# 39, when I checked for power the white wire had no power and I had the engine running plus I checked with a test light and made sure the pin was seated good. Thier is not a fuseable link for the switch. I put a 10 amp fuse in the fuse box in the engine compartment and still no power. This is a new unit that I just bought. I checked the pressure switch also and it was bad. Would the pressure switch have any thing to do with the Switch-Pac? Sent for a new pressure switch and received the wrong one yesterday. Have any of you have any problems with your electrical. Any and all answers greatly appreciated.

 

[MoparDave]

The white wire must never have power applied to it, it is a grounding circuit. All the switch does is close the path to ground. The ecm see the ground on pin 39 and knows to enable the pacbrake by grounding pin 42 that feeds the relay. If you have applied 12+ you may have damaged you ecm. The pressure switch in normally closed, and will signal the compressor to run. When pressure is reached the switch will open and signal the compressor to stop. This is a 12+ circuit feed by the compressor relay. Solenoid is what activates the butterfly it is controller by the solenoid relay and is 12+ to the solenoid, the solenoid relay itself is grounded by the emc from pin 42 allowing 12+ to pass to the solenoid.

 

[WStrmiska]

Thanks MoparDave for the quick answer. I did'nt put any power to the 39 pin, I just checked with a test light (no batteries in the test light) to see if it had power at the wire. I'm clear on the 39 pin now. I'm hopeing its the pressure switch at the air tank as I was not getting any power from the pressure switch at the tank to the air compressor. The folks where I bought the unit said I needed a new pressure switch. Hopefully this will fix my problem. Will know next week when I get my PW. Thanks again Dave.

 

[Pacbrake]

Dave thanks for taking care of this for me you are right on how the system works.