USGear Exhaust Brake: Operate off of PCM?

[RobG]

I had the muffler shop finish up the installation of my DD 4" exhaust today, and also had them put in my US Gear Exhaust Brake. Now to do the wiring.

What I want to know is this: Is there a way to avoid installing the pedal-mounted microswitch, and instead let it operate off of the PCM like the Jacobs and other 24V brakes do? What I'm going to try to do right now is just install the wiring and let the pushbutton switch turn the brake off and on without the microswitch. On my '96, I rarely used the brake other than to slow on a grade, so this could work fine for the time being.

Rob

 

[Thomas]

The Jacobs E-brake and the Pacbrake use pin #20 of the ECM—not the PCM.

The 12 volt signal from pin #20 is what actually actuates the vacuum solenoid. I have no idea what current is flowing through the vacuum solenoid but imagine that a relay could be safely attached to pin #20. You could then use the relay for whatever you wish—like replacing the microswitch.


[This message has been edited by Thomas (edited 03-05-2001). ]

 

[RobG]

Okay, wiring is done. I'm not sure it's quite right, because with the microswitch open, the brake would engage. With it closed, it'd disengage. That's odd. Tried swapping the wires, no change. With both wires unplugged, it works off just the switch like I wanted.

Tell me please... I'm not as electronically-literate as I'd like... what kind/type/size relay should I get, and how will it hook up? I'll assume that two leads will be the wires I have now, and another lead to #20 on the ECM. Any others?

Thanks!

Rob


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2001. 5 RAM 3500 QC 4x4 ETH/DEE Silver/Agate 4. 10 USGear OD, Rickson 19. 5 Wheels, Edge EZ, SPA Guages, Psychotty, Firestone Airbags, Hellwig Rear Swaybar, Torklift Superhitch & Camper Tiedowns, Mag-Hytec Diff Cover, DD 4" Exhaust, US Gear Exhaust Brake, etc.