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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: meandmyarrow on October 15, 2013, 06:11:30 pm

Title: AC and Heater Problems
Post by: meandmyarrow on October 15, 2013, 06:11:30 pm
Hey Everyone -

This is my first post to the forum and my first crack at working on my girlfriend's new (old) 1987 Chevy r10 with a 305.

So I went through the whole hassle of replacing the heater core today after the defroster was spewing mist (that smelled like coolant.)  It left a smear on the windshield and after looking up the problem it appears that it should be the heater core.  I also checked the hoses and everything seemed ok. 

So flash forward eight hours and the new heater core is in.  I went to turn on the heat to filter the new coolant through everything and bask in a job well done and lo and behold it wasn't blowing.  The AC either.

When I turn on the ac or heat you can hear the idle change, and the two pipes going to the ac unit under the hood feels cold.  So now I am left scratching my head.

Does anyone know why both ac and heat wouldn't work?  I figure maybe I screwed something up with the heater box...  In a couple of days I will take the glove box back out and check the connections, but first I figured I'd check with you guys.  Is there something simple that I could have screwed up that would explain nothing blowing from the vents?

Thanks,
Drew
Title: Re: AC and Heater Problems
Post by: Captkaos on October 15, 2013, 07:00:50 pm
The coolant system is full correct and all the air is out correct? How are the hoses connected?  Is the engine up to operational temp?

As for the fan, did it work before?  Are all the plugs connected?  Is it blowing but Not out of the vents?

Chris Lucas
73-87chevytrucks.com
captkaoscustoms.com
squarebody.biz

Title: Re: AC and Heater Problems
Post by: VileZambonie on October 15, 2013, 07:01:43 pm
Do you mean the blower isn't working? Is it plugged in?
Title: Re: AC and Heater Problems
Post by: bd on October 15, 2013, 08:09:29 pm
^^^^^ X2
In addition, make sure the black ground wire is securely connected directly to clean metal on both the blower motor case and cab sheetmetal.  Check that the harness plug is fully seated into the blower relay located at the right side, top of the heater housing under the hood.
Title: Re: AC and Heater Problems
Post by: meandmyarrow on October 15, 2013, 09:14:45 pm
Thanks for the replies... here's some more info.

- The coolant is full, checked at operational temp... I didn't think you had to bleed the radiator fluid, so there may be air in it...

I will have to double check the ground wiring.  I will also double check the blower relay plug, since I did knock it around trying to get the old hoses off.

The fan did work before, that how we found the mist from the defroster in the first place... but before I went to do this fix the heater didn't seem to be working.  Right now, nothing is blowing in at any setting for the ac and heater.

I'm going to double check those plugs and see if I screwed up something simple... but any ideas are good ones.

Thanks again!
Title: Re: AC and Heater Problems
Post by: meandmyarrow on October 15, 2013, 09:59:55 pm
Well, I think we can wrap this one up... I never claimed to be smart, yet sometimes I even amaze myself.  The blower wasn't plugged in.  It was hooked back up, but the connection was off, a jiggle and there she goes!  Thanks for your help guys.

Here's a pic of the black beauty :
Title: Re: AC and Heater Problems
Post by: bake74 on October 18, 2013, 10:45:29 am
    Nice looking truck.