I lost my jakes last week, so I put a new relay in and nothing. I put a new on/off switch in and it worked again all 3 stages. But today only 2 stage will work and some time when its on 3 it will work. Has anyone else had this happen or know what the fix would be?????

There are 3 wires under the valve cover going to each stage of jakes, one going to each of the solenoids. The wires could be getting loose in the spade conectors. You could pull the cover off and see if they are all good and tight. I had this happen to my truck, all stages would work fine then out of the blue one stage would mess up. It was a loose wire on the solenoid.
Mike

Clutch Switch?

If the clutch pedal switch was the problem it would not work at all.

He said:I'll agree that there's a bad connection somewhere leading to the individual stages.

Could be under the valve covers, could be in the wiring between the dashboard switch and the engine.

If it has a separate switch for on/off and for 1, 2, and 3 stages the 1/2/3 switch could be defective.

Also could be a defective solenoid on one of the jake units.

Probably right but if he just started having problems the clutch Switch will work and then cut off in the beginning.

Thanks for your info I pulled the dash aprt and followed the wires to the fire wall. the connection was losse on the motor side(had to tighen up the bolt holding wiring harness on).. I hope that was it. Seems to be working for now.