Topic: Fan speed
in Forum: C3 Electrical
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Hi all, looking for some advise of where to start troubleshooting. So for the past months, my car has been going through an engine and transmission rebuild. Now that it's back together, i'm starting to tackle all the little items since winter slows things down a bit.
Yesterday while adjusting my fan controller, i was playing with the heater control switches to make sure hot water was circulating in the heater core and i noticed i had no fan speed changes from low to high. I didnt yet bother with the basic testing of the switch, but i did notice that when the key was in the accessory position, i could hear the fan blowing. If i remember right, the fan is always blowing on low ? and i know that for the high position, there is a high speed relay under the hood to check.
So my question is besides the basics of 1) Fuse 2) high speed blower relay and 3) switch. Is there any other area i would need to check ?
Before the motor and trans came out, it was working just fine which has me wanting to believe it's something simple such as something unplugged (or maybe i'm just hoping it's that simple :-) )
Thanks in advance
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Darin - It's been awhile since I worked on a 80 Vette fan system but here are some ideas. Verify the ground wire for the fan down by the starter got hooked back up when the engine went back in. This will cause issues if not connected. You can perform a simple ohm test on the bower resitor to verify it's good. I have attached a wiring diagram for your review. Keep us posted what you find.


You know I was hoping I would be lucky enough to find that ground wire not connected since I knew exactly which one you are referring to. But, no. I did remember to connect it. But to be safe I will check continuity this weekend. If that's good then more in depth trouble shooting.
Thanks for the great suggestion and diagram though.
Also would you happen to remember where the fan resister is located? I know the blower relay is under the hood.
|UPDATED|1/23/2017 5:47:04 PM (AZT)|/UPDATED|
|UPDATED|1/23/2017 5:47:04 PM (AZT)|/UPDATED|

SHELBYVILLE, TN - USA
Joined: 7/5/2002
Posts: 3942
Vette(s): 1976 L48 auto
1978 L82 4speed
1994 LT1 6speed
1978 L82 4speed
1994 LT1 6speed
Just a thought to throw out there, there is another ground wire(at least in 76 and 78,can't swear on your year). Ground wire on the starter bolt. It grounds the instrument cluster and surrounding area. I know i have screwed up and actually put the ground wire on the hot terminal while installing a starter(motor was out and i didnt pay that close attention unhooking the wires once we got the motor back in), it did some weird things, fortunately it didnt damage any of the gauges, but while hooked up that way, none of them worked 'properly' (they all pegged out).
in Forum: C3 Electrical
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