Carrier Comfortpro Apu not blowing air

Does the fan come on at all? Might be worth the hundred bucks or so to pop by the dealer for a diagnostic.

 

I agree. Anything else without a proper diagnosis will end in just throwing parts at it.
It could be a blown fuse somewhere or a faulty blower motor, or simply a disconnected wire.

 

Mine started doing something strange a couple months ago .
Occasionally when I would start it and turn the AC on and it ran for a while a message would come up saying " check apu engine "
Or occasionally when I would start it would show a " restarting " message but would never crank over .
When it would show the check engine message it never shut and kept right on blowing cold air and never had a code .
Simply shutting it off and restarting it solved both issues and wouldn't happen again for weeks .
A couple days ago it started doing it every time I started it and the comfort mode wouldn't work although the engine would start so i just ran it on continuous with the message displayed ..check apu engine.
Yes this is windy lol......so today when I stopped ..before I started it i unplugged both connectors from the control boxes in the apu housing along with the harness to the alternator and starter and plugged them all back in and fired it up ...wala ! No messages and it's been running a couple hours now .
All connectors appeared clean and tight .
Ohhhhh and I wash out the apu engine and housing every couple months so i put dielectric grease on the connections.
What did i do ? Did this reset something? Cause it's doing everything its supposed to now .

 

Why is it every summer we have drivers weeping that they cannot get cool over something that will sit there and do nothing until it's pulled off every possible connection wire and cleaned, wait a hour and plug back in.

Sure it's great driving that wonderful plush tractor trailer, but you have to do some scraping now and then for your repose in the hot summer night after your labors.

 

You know I'm a clean freak heavy when I wash my apu engine lol.

 

Checked with my shop pal today and he said I reset the ECM.
Hasn't sent a message since and does what its supposed to do .

 

There’s a CAT5 cable which runs from the control panel to the CECU. That often works its way loose.

‘Resetting the ECU’ sounds like bull (excrement) to me, personally.

 

Yeah I think you are right but will say it ran flawlessly for another 4 nights which beat going into a road shop but about 3 this morning it started sending messages again , when I started it this evening I had repeat the process several times until it would stay running and the starter sounded ugly .
Its locked on continuous now and will go into the shop tmw when I get home ...starter is only 6 mos. Old so it's under warranty if that's the problem.

 

The CAC cable was loose .