Hey all. Been a while since I posted. Evacuted New Orleans before the hurricane season and have been on the road working since. I guess it's been about 8 months since my last confession, uh... post.

Anyway, as life would have it, I've found my way to Iowa of all places and it's bitterly cold for me and my truck as I'm a Southern boy.

The ole flatbed keeps on tickin' long as I have 'er plugged in.

But, the heater situation is non existent.

Background:

Warms up normally and thermo cycles as it should. I can hear the ac click on and off on window defrost occassionally. Seems like it always did that. The temperature **** seems to actuate whatever door it should, as I hear something move with a slight tention on the **** when I cycle it from cold to hot. Moved it slow and fast to see if something was stuck. That did nothing.

Here's the funny thing. When I'm moving on the road and it's blowing cold air to the windshield, I can move the selector from windshield to any other setting and back to windshield/defrost and a puff of hot air will come out to the window for a few seconds and then blow back to cold air. Mind you, it's not cold air-conditioned air best as I can tell, but just ambient/outside air.

If it'll blow hot air for a few seconds, this leads me to thing the heater core is not plugged, but I could be wrong.

Just wondering what your thoughts are before I take it somewhere to be checked. And would you recommend the dealer fix it or someone else.

Thanks in advance and I can't wait till winter gets here, according to the locals, this is just the tip of the iceberg, if you'll pardon the pun. Gets to be below zero regularly I'm told, later in the season.

I think I'm going insane.

 

First thing that I'd check if it were mine is to grab both hoses going to the heater core once the truck is well warmed up and see if one is cooler than the other. If it is, it could indicate a control valve problem (if your truck has one) or could be a plugged heater core. If there is a difference and there is a control valve inline with one of the heater hoses, I'd check to make sure that it was opening and if not, try to wire it open and then see if I got heat. If there is a temp difference in the in and out hoses but the control valve is functioning, it may be your heater core.

If both hoses are equally hot, then it may be a heater door problem. Your description of a "puff" of hot air almost sounds like a bad vaccuum actuator on the door that will momentarily open and then bleeds back closed. I don't know if your truck has a vaccuum actuated heat door but if it does, I'd check to see if the actuator would hold a vaccuum. It could also be a cracked vaccuum line going to the heat door or any one of a number of other problems but that at least gives you a place or two to start.

Good luck and stay warm.