Peterbilt cruise problem

I have a 2015 389 glider. The "set" position on the cruise control keeps cutting out. Resume works, jake brake works, brake lights are not on, brake switches are all new. I can hit resume and it will automatically go back to the last speed it was set at. It will go to high idle with the brake set but I cannot dial it down. It will turn off if I tap the clutch pedal going down the road. The cruise switch is new, so is the clutch switch. The heck is going on?

 

Gotta hook up to the ecm and monitor the cruise switch input to see whats hapeneing.
Worked good before and just happened or has never worked right? Datalinked cruise or hardwired? Engine?

 

It has worked before. It kinda acted up this way before and I switched out the dash switch. It has been acting fine for a while but now it's being intermittent again. It has a Detroit. I'm not sure how the data link is wired, it's a Fitzgerald truck so however they do it...

 

I have the same problem. Same truck too, 2015 Fitzgerald Pete 389. Some days it works fine, others not so much. Seems to be wet or damp days give me the most issues. We’ve replaced the clutch switch, dash switch,....thinking something may be wrong in the wiring harness. It’s really getting frustrating.

 

Check the brake switch.

 

Any conclusions on this issue? I have a similar problem but worse. No cruise, jakes come on…..but literally seem to work only enough to slightly hear them. I can only feel the effects if I bobtail. 2nd stage seems weaker than 1st stage, and 3rd stage is still only a slight fraction of how 1st stage used to be. This happened after a motor swap. Same motor out of an identical truck with same setup. 2015 389 Fitzgerald Glider. 60 series Detroit. Motor blew, swapped em. Now no idle up, cruise, or usable Jakes. Any input is appreciated

 

Not to worry, but all you guys that are having this common issue, its NOT just because you have a Fitzgerald truck. I've got a 1999 Pete 379 with a factory installed Detroit. The issue I've experienced, intermittently of course & for years, has been my truck won't idle up when I'm parked. I've replaced both dash switches, brake & clutch switches, main cab wiring harness, the dash jumper wiring, an ECM when the original one died, etc..etc, blah, blah, blah. All ECM parameters are "set" correctly. Nothing I've ever done has solved this "condition". I have just accepted this just a Peterbilt/Detroit thing.

 

I have the same issue with a 2018 Pete with cummins x15. Problem just started a few weeks ago. Haven’t had time to replace the clutch switch. I’m going to try that then move to the dash switches. Hopefully one of them solves the problem. I really need my high idle in the winter.

 

Have a 2014 389 pete. Click cruise to high idle. Will go for a bit daytime running lights come one and off as well parking brake indicator light on dash. What could it be?

 

did you find issues