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Heater blows cold. Help!

1424 Views 7 Replies 6 Participants Last post by  MidwestCustoms
My trucks heat has never been great in the year that I have owned it, but today it started to blow cold, which sucks because it has been between 5-30 degrees here lately. The temp gauge is at 185 as always and there is plenty of fuid in it. Maybe the heater core? A freind reverse flushed his heater core and it unplugged a bunch of junk from it and he had heat again. Any ideas before I take it to a shop? Thanks
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If it were 5 degrees I would have the front cover on the truck. Maybe you do also need a flush out.
Next, do you plug it in at night, and how far do you drive. In weather that cold, I don't see heat until I have driven 4-5 miles.
Flush it again. What kind of "junk" came out the first time?
Check to make sure the vacuum operated plenum is opening to allow heated air to go through the air ducts.
They aren't know to blow very hot. Go to a parts store and get a thermometer to measure the temp. Mine will only get as high as about 100 degrees and that is with both covers on and a fair distance of driving. I see you have a lt - does it have the climate control also? May want to look there. If both the lines going in and out of the heater core are hot - it isn't there.
Thanks everybody, I went and ran the truck later that same day and it was working fine then. Got me? I am waiting for it to warm up around here and I am going to reverse flush it anyways. I do plug it in when it gets to the teens and under. We had a week here of 10-15 below w/o the windchill and it was working normally again. It normally takes 5 miles or so also on my truck to blow heat. Thanks again ,wish I could respond quicker, can't always get time to get to the computer though.
I had a recent failure with the heater/defroster on my 02.
Truck had been warmed up several hours earlier. Outside temp -10 deg F.
I drove a few miles with heater set to vent/floor. Windows started to frost, so I switched to defrost. A minute or two later the frosting was worse. Turned fan to high, and realized it was still on vent, (not defrost), and it failed to full heat, and both LED's on outside air and recirc pushbuttons were on. :think:
Kept driving for 30 miles to destination. Truck idles for about 15 minutes, with same failure. In the fuse block left of instrument panel, I found Fuse HVAC 1.
Pulled this fuse, Hvac pushbutton lights went out, fuse was NOT blown, re-installed fuse, and the heater/defroster started to work as expected. Has been working since.
When I pulled the fuse, the truck was still running, so I'm not sure if I would have just turned the truck OFF, if that would have fixed this problem.
Now I don't know if something is worn or ready to break, or if this was a one time failure because it was so frickin cold out.
Time will tell.
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Thanks for the tip, if it happens again I will try that. Hopefully that's all that it needs and not a costly heater control panel. Time will tell!
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