[kiwijetpilot]

Hi all,

Had a look through other posts and FAQs etc, but couldn't find an answer to my problem.

Basically, when starting the vehicle from cold, in ambient temperatures of around 10C-15C, the HVAC display is normal for about 5 seconds, and then the dreaded book appears. Stopping and re-starting the vehicle doesn't clear it. The HVAC then operates in "full hot" mode. Once the vehicle has come up to temperature and driven a few miles, stopping and re-starting the vehicle does not result in the "book", and for the rest of the day's driving the "book" stays away and everything works correctly.

My guess is that the HVAC, when cold, is demanding a valve or flap open, and when it doesn't do as commanded, it throws the error. Once it is up to temperature, it no longer commands the valve to move and all is peachy. That's what it feels like, anyway.

I have swapped out the HVAC control module for another, and the problem is the same with both.

Does this sound familiar to anyone? Do I have to spend a day tearing my dash apart, cutting vents, etc...???

Any help appreciated!

 

[leftlanetruckin]

The HVAC does it's self diagnosis at every start up.
More likely a blend motor sticking, which free's up as the day goes on.
You can search the threads here to find the culprit, along with short cuts to test etc.

Martin

 

[Bolt]

As Martin says, it is probably something simple. I vote for blend motor as well, but could be a sensor with a loose connection as well.
However, without a P-38 specific test tool like a BBS Nanocom, you are shooting in the dark.
A nano will tell you exactly which component needs attention. You can watch things in real time and read any logged codes as well.
No hacking into ducting required!

 

[ColoradoCrow]

My guess would be the fresh air/ recirc motor flap on the outer most sides of the truck.
My passenger side motor flap sticks. I unplugged it and taped it closed permanently. It throws the book symbol about 7 seconds after startup every time.

 

[annette]

did you try to recalibrate the flap motors?
that gets (often) these issues sorted.. maybe it oes past the allowed about 90 degree angle that it travels.