Blower switch not working - The 1947 - Present Chevrolet & GMC Truck Message Board Network

iufan71 · 06-19-2003, 09:50 PM

Ever since i have gotten my 78 GMC a few months ago,the fan switch has not worked. I have factory a/c,though its not working right now. But i figured i could get the fan to turn on even if just for the vent of fresh air. What should i check first and so on to figure why im getting nothing?

*mike reeh* · 06-19-2003, 10:23 PM

turn the key on and listen real close to the blower motor to see if its turning at all.. they are supposed to always be on "low" even if the the vent selector is switched to OFF.. Then check the little plug that plugs into the blower motor.. Make sure its hooked up and all. Then check for 12 volts at that plug.. If it has 12v then its the motor...

if it doesnt have 12 volts then its probably the relay or the resistor which are both right there bolted to the AC box.. its really an easy diagnosis.. Then theres always the possibility that its the switch but I aint never seen one go bad..

let me know if you need more info or help and good luck

mike

**old Rusty C10** · 06-19-2003, 10:58 PM

reachunder the dash and make sure the fan is plugged in ive seen the plugs fall out or be damaged due to shorts and not make contact

houston6 · 06-19-2003, 11:51 PM

this will sound silly but have you checked the fuse.would you beleive my last truck gave me a fit with the tail lights and i was all set to rewire the dang things then it dawned on me to check the fuse man did i feel like an idiot.bit it was just a matter of my not thinking which is normal for me lol

06-19-2003, 09:50 PM	#1
iufan71 Registered User Join Date: Apr 2003 Location: Indianapolis,IN Posts: 138	Blower switch not working Ever since i have gotten my 78 GMC a few months ago,the fan switch has not worked. I have factory a/c,though its not working right now. But i figured i could get the fan to turn on even if just for the vent of fresh air. What should i check first and so on to figure why im getting nothing?

06-19-2003, 10:58 PM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,277	reachunder the dash and make sure the fan is plugged in ive seen the plugs fall out or be damaged due to shorts and not make contact __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

06-19-2003, 11:51 PM	#4
houston6 Registered User Join Date: May 2003 Location: north wilkesboro nc Posts: 221	sounds silly but this will sound silly but have you checked the fuse.would you beleive my last truck gave me a fit with the tail lights and i was all set to rewire the dang things then it dawned on me to check the fuse man did i feel like an idiot.bit it was just a matter of my not thinking which is normal for me lol __________________ Scott

06-19-2003, 10:23 PM	#2
mike reeh 5 day ban, learn to behave. Join Date: Nov 2002 Location: san diego, ca Posts: 684	turn the key on and listen real close to the blower motor to see if its turning at all.. they are supposed to always be on "low" even if the the vent selector is switched to OFF.. Then check the little plug that plugs into the blower motor.. Make sure its hooked up and all. Then check for 12 volts at that plug.. If it has 12v then its the motor... if it doesnt have 12 volts then its probably the relay or the resistor which are both right there bolted to the AC box.. its really an easy diagnosis.. Then theres always the possibility that its the switch but I aint never seen one go bad.. let me know if you need more info or help and good luck mike



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