Alright boys and girls, in the midst of trying to determine how to install my electric brake controller, I dewired a lot of hacked stuff like the random fog switches and crap hiding behind the dash. I also started troubleshooting my pacbrake to determine why it's not currently working. I don't know which model it is exactly, but it does NOT have a compressor with it. It looks as if it's operated by the brake booster and a solenoid that directs airflow from one end of a diaphragm to another. The in cab switch works, as I verified it by tracing the signal wire into the engine bay. It runs to a switch at the end of the throttle travel. Looks like it's how it completes a circuit, and send the signal to the solenoid to activate. Anyways, when the throttle is stopped the power DOES make it to the solenoid. My logical progression leaves me to believe that the solenoid is bad. Is this a common part to go bad? How can I test it? I don't know where to go from here or what else to do.

Sorry for the long post guys. Thanks,
Shawn

 

Well I figured it out. I guess I posted too soon. The plunger that the solenoid pushes was froze, and the solenoid just didn't have the oomph to push it. Free'd up the plunger and I was good to go. Now the cylinder moves in the bracket a bit, and when the brake is applied exhaust pressure can overcome the diaphragm force making it useless. I'll tighten it up later and should be golden.

Shawn

 

Check all the external linkages for wear & gauling. Lube well. This is the Pacbrake weakness.

 

Does the pacbrake work on an empty truck? It actuates at idle, I checked everything and everything looks like it's working properly. It just doesn't seem to do much at speed, and I don't have a trailer around the house to hook up to and test it out with. Is it load dependent?

Shawn

 

It's throttle dependent. There should be a switch on the throttle linkage that turns the Pac off when you give it fuel.
Take the vacuum switch apart and clean it well, seems to be a problem area as I've had to do it on several trucks.

 

Yea, I did that and got it working. It just doesn't seem to do much say if you let off the throttle on the expressway. I'm thinking it might have a lot to do with being auto, and no lock up when coasting. Anyone else think so?

Shawn

 

You defiantly need lock up for the brake to work. Some people install a mystery switch that works off the same one used for the Pac or you can install a separate one.
Instructions http://www.tstproducts.com/Torque%20...p%20Switch.pdf

 

Thanks a ton, that definitely answered my question. I think I might just buy a controller though, since I KNOW i'll forget to unlock it and stall the truck.

Shawn