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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: furoc on April 02, 2014, 07:41:42 pm

Title: Heat/AC issues
Post by: furoc on April 02, 2014, 07:41:42 pm: I have been having problems with my heater not blowing. I have checked the fuses, replaced the motor, relay, and resistor. I get nothing out of it at all. Any suggestions would be great.

This started with it blowing out about half as powerful as it normally would, and all of a sudden stopped.
Title: Re: Heat/AC issues
Post by: furoc on April 02, 2014, 07:43:15 pm: Sorry I forgot to add that it is a 1986 C10 Silverado. My fault :)
Title: Re: Heat/AC issues
Post by: bd on April 02, 2014, 09:35:06 pm: First - make sure that the blower motor is properly grounded through a short 12-gauge wire that securely connects bare metal on the blower motor mounting flange to bare metal on the cab. Also, make sure that the cab is properly grounded through the braided 5/16" strap that connects the firewall to the back of the passenger side cylinder head.

Second - check for power to the blower motor with a test light or voltmeter. If there's zero or very low voltage at the blower, inspect the selector and blower switches behind the dash on the control head assembly (and their respective harness connectors) for any signs of heat damage/melting/burning. The Pack-Con style terminals don't manage high current very well and have a tendency to concentrate heat and distort/burn. If there's any evidence of heat damage, replace the switch and connector and coat the new terminals with dielectric grease or antioxidant.

Please, let us know the outcome and whether you need further assistance.
Title: Re: Heat/AC issues
Post by: furoc on April 05, 2014, 09:47:44 pm: Well I replaced my blower motor switch, but it wasn't the solution at this point. No visible burning on any of the connectors so I don''t think that is the problem. I guess it is time to yank the blower motor back out to ensure that all of those connections are still in place. I know that I didn't mess with anything and put it all back as it was, but there is always the chance.
Title: Re: Heat/AC issues
Post by: bd on April 05, 2014, 10:11:57 pm: Do you have 12 volts on the brown wire connecting to the selector switch?
Title: Re: Heat/AC issues
Post by: furoc on April 11, 2014, 09:11:14 am: I am going to put a voltmeter to it today. Due to illness in my family I have been tied up and unable to get to fixing it.