A/C works on HIGH only
Thread Starter
Racer
Joined: Jul 2007
Posts: 397
Likes: 1
From: Tucson Arizona
A/C works on HIGH only
A/C is working, but only blows on HIGH. Trying to determine why this is. I was wondering if anyone has had this problem in the past and steps they took to correct it?
Fuses, resistors, motor blower, switch itself, etc ... not really sure where to start looking or location of everything.
It's dark now and I lent out my repair manuals to my uncle (getting them back Sunday). I'm planning on investigating a little more then but any help I can get will be much appreciated. Vette is a '74.
Thanks in advance!
Fuses, resistors, motor blower, switch itself, etc ... not really sure where to start looking or location of everything.
It's dark now and I lent out my repair manuals to my uncle (getting them back Sunday). I'm planning on investigating a little more then but any help I can get will be much appreciated. Vette is a '74.
Thanks in advance!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
It's not the blower motor, or it wouldn't be working at the HIGH speed setting. It could be a fuse, as the HI fuse is separate and not in the fuse panel. It could be the resistor pack (I think..my schematic is packed up, so I can't tell you for sure). I doubt that the switch is the problem; the greatest current flow thru the switch is with the HI speed setting, and it is working.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Check the heater AC fuse.(I have a 73 diagram and a 75-no 74)Then just for fun run an extra ground to the blower motor while in the lower speeds.I know some are going to say the blower is grounded with the wiper motor via the black wire at the starter mounting bolt and my 73 diagram shows it that way -but my crappy 75 diargam shows that ground going all the way back to the heater switch.Not sure if your 74 is closer to 73 or 75 specs.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Yep. The grounding methods used for C3's [early years, at least] were pretty skimpy. There is a ground wire running to a brass spade lug which is just placed under one of the mounting sheet metal screws. And the lug is placed OVER the painted surface on the housing. Not the best design to get a good ground. Check that all out [if you can get to it]; but I suspect that's not the trouble with yours, as the HI blower speed works OK.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Yep. The grounding methods used for C3's [early years, at least] were pretty skimpy. There is a ground wire running to a brass spade lug which is just placed under one of the mounting sheet metal screws. And the lug is placed OVER the painted surface on the housing. Not the best design to get a good ground. Check that all out [if you can get to it]; but I suspect that's not the trouble with yours, as the HI blower speed works OK.
Intermediate
Joined: Mar 2007
Posts: 40
Likes: 1
From: Durban KZN
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