Threaded Mode | Linear Mode

Casper · 02-01-2021, **(Subject: 2014 Head Scratcher )**

2014 Pete 386:

Have had trouble with the HVAC for quite some time, have thrown everything at it you can imagine, including:
New HVAC, New actuators, New CECU3....
Problem:
Everything on the HVAC is 'backwards'...when I say backwards I mean, Hot is Cold and Cold is Hot.
When checking Voltage: Clockwise should be 12 v., but it's 1 v., Counter clockwise should be 1v., but it's reading 12 v.
No one seems to have run into the same problem and I'm wondering why "I" am the Odd-Ball? Any input??

snailexpress · 02-01-2021, **(Subject: 2014 Head Scratcher )**

(02-01-2021 )Casper Wrote: 2014 Pete 386:

Have had trouble with the HVAC for quite some time, have thrown everything at it you can imagine, including:
New HVAC, New actuators, New CECU3....
Problem:
Everything on the HVAC is 'backwards'...when I say backwards I mean, Hot is Cold and Cold is Hot.
When checking Voltage: Clockwise should be 12 v., but it's 1 v., Counter clockwise should be 1v., but it's reading 12 v.
No one seems to have run into the same problem and I'm wondering why "I" am the Odd-Ball? Any input??

Did you check driver manual for this truck? There is what was with my truck, in every truck I drove before, AC button ON position when button light is on. In my truck Volvo decide to set it backward. Light off AC on. It was in driver manual.

Casper · 02-01-2021, **(Subject: 2014 Head Scratcher )**

I'll double check that!
Thanks for the heads up

Moose · 02-02-2021, **(Subject: 2014 Head Scratcher )**

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.

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Casper · 02-03-2021, **(Subject: 2014 Head Scratcher )**

(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?

Coronado126 · 02-04-2021, **(Subject: 2014 Head Scratcher )**

(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.

Casper · 02-06-2021, **(Subject: 2014 Head Scratcher )**

***Yes, I've ordered the Actuator directly from "Dorman", which is the same as what I originally purchased Through Peterbilt. There's no color coding, but there are Letters on it that dictate which actuator.

Waterloo · 02-07-2021, **(Subject: 2014 Head Scratcher )**

(02-06-2021 )Casper Wrote: ***Yes, I've ordered the Actuator directly from "Dorman", which is the same as what I originally purchased Through Peterbilt. There's no color coding, but there are Letters on it that dictate which actuator.

If this started with the new actuator, the Dorman actuator, I would suggest going to Peterbilt and getting an OEM one and trying that. Sounds like that may be your issue if I am reading this correctly... Some aftermarket parts are fine, others not so much. Been there, and done that.

I just bought two blend door actuators from International for my truck, as one had failed. One thing I did discover is that the new actuators are now made in Korea vs China. They are much beefier, or stouter, take your pick, over the Chinesium actuator it replaced. The Chinesium one was a Dorman unit, which I have bought before without issue, other than their failure rate after a year or two. How come I can own a car for twenty years and the blend door actuators still work? What the hell is going on here with these things? Seriously, this is not rocket science.

The new OEM unit was noticeably different quality wise, heavier and looked to have used better plastic. Hopefully it lasts longer than a year or two. The Dorman and the old Chinesium OEM actuators were identical in my book, the new Korean sourced ones appear to be much better, but only time will tell. Maybe PACCAR has done the same with suppliers?

Coronado126 · 02-09-2021, **(Subject: 2014 Head Scratcher )**

(02-06-2021 )Casper Wrote: ***Yes, I've ordered the Actuator directly from "Dorman", which is the same as what I originally purchased Through Peterbilt. There's no color coding, but there are Letters on it that dictate which actuator.

If that dealer sold you a Dorman part, then they definitely sold you a lower qaulity one.

PACCAR factory sources their actuators from Climatech. If you Google them, or go to peterbiltparts.com and search there, you will find the exact part with color and letter listed along with it's OE part number.