a/c blows fuse when on high - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BIGCHEVYMAN · 06-30-2009, 09:43 PM

This has been a pain in the a$$ for the past few days.
My a/c works great until you put the fan switch on high and the the fuse blows.
I have checked the relay,fan switch and they are fine. Any suggestions ? thanks

pokethesmot · 06-30-2009, 09:57 PM

are u sure u have the right sized fuse? i use to have the same problem with my stereo in my old truck till i found out the fuse wasn't the right size

**old Rusty C10** · 07-01-2009, 10:07 AM

it shouldnt take more than a 30 Amp fuse for the AC ..if the relay checks good id start searching the wiring for something that arcs

dieseldr4 · 07-01-2009, 03:52 PM

yeah, a 30 amp fuse is more than enough for the blower circuit, most times this can be traced to a blower motor that has to high of an amp draw on high (this happens when it is old and the brushes are really close to the commutator)... same thing with a/c cluthes, if it is close to worn out and the gap is too big on the clutch, it will draw too many amps and pop the fuse... hope this helps

454HO · 07-01-2009, 05:16 PM

Could be debris in the fan. Pull the motor and clean it out. Would be a good time to oil the motor shaft and make sure it spins freely. Also check the speed control resistors inside the airbox. I have seen them blow up or short together. That usually kills one of the intermediate speeds though.

06-30-2009, 09:43 PM	#1
BIGCHEVYMAN Senior Member Join Date: Apr 2002 Location: Portland , Tennessee , United States Posts: 1,024	a/c blows fuse when on high This has been a pain in the a$$ for the past few days. My a/c works great until you put the fan switch on high and the the fuse blows. I have checked the relay,fan switch and they are fine. Any suggestions ? thanks

06-30-2009, 09:57 PM	#2
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: a/c blows fuse when on high are u sure u have the right sized fuse? i use to have the same problem with my stereo in my old truck till i found out the fuse wasn't the right size __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

07-01-2009, 10:07 AM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,287	Re: a/c blows fuse when on high it shouldnt take more than a 30 Amp fuse for the AC ..if the relay checks good id start searching the wiring for something that arcs __________________ 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!!

07-01-2009, 03:52 PM	#4
dieseldr4 Registered User Join Date: Dec 2007 Location: apple valley , ca Posts: 125	Re: a/c blows fuse when on high yeah, a 30 amp fuse is more than enough for the blower circuit, most times this can be traced to a blower motor that has to high of an amp draw on high (this happens when it is old and the brushes are really close to the commutator)... same thing with a/c cluthes, if it is close to worn out and the gap is too big on the clutch, it will draw too many amps and pop the fuse... hope this helps __________________ be a site supporter

07-01-2009, 05:16 PM	#5
454HO Registered User Join Date: Apr 2005 Location: Austin, TX Posts: 1,224	Re: a/c blows fuse when on high Could be debris in the fan. Pull the motor and clean it out. Would be a good time to oil the motor shaft and make sure it spins freely. Also check the speed control resistors inside the airbox. I have seen them blow up or short together. That usually kills one of the intermediate speeds though. __________________ - Greg



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