2014 Head Scratcher

[Coronado126]

(02-03-2021 )Casper Wrote:  

(02-02-2021 )Moose Wrote:  You say 'everything' but don't mention fan speed & mode control. Cab controls, sleeper or both? Makes me wonder if a prior harness repair was done and the polarity got reversed. I looked through some schematics I had for one of my 389s and while it doesn't give polarity, it seems like that could happen. You would think though, the CECU would catch that and present a DTC especially if it has the ATC option. I'm assuming yours is manual control.

I believe if I had a wiring diagram specifically for this vin number, it'd be easier to find the issue, however...I have been unable to obtain a diagram that is vin specific.
I replaced the HVAC control unit as well (forgot to mention that). The HVAC works perfectly in the sleeper, so there's no issue there.... And you may be correct on the wiring harness...But when I checked/traced the wiring, it doesn't appear as though anyone has ever been in the wiring. Fan speed is fine, mode control works fine?? I'm open to suggestions and thoughts on this?

You said this a long term issue, for my clarification, did this problem exist when you bought the truck, or start after that?

Just to confirm but you installed the correct actuator right? PACCAR uses color codes on some position/temp actuators, and getting the wrong color installed led to some goofy issues that I had on a fleet truck of ours. I had installed a 'green' where a 'white' needed to be and the heat was all over the place.