Heater/AC blower question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dean · 05-10-2003, 04:50 PM

I have a question about the blower speeds on one of my K20s. A friend borrowed my manual so I can't rember how I fixed this on another truck. I can only get the blower to work on one of the switch settings (third one down). It will not work on high or low. Isn't there a rheostat or something in the system? Or do you think it is the switch itself? Thanks for your help. I figured this would be quicker than going to get my manual.

Dads72 · 05-10-2003, 05:22 PM

For what it's worth, I seem to recall that the high speed switch is by itself - maybe has it's own relay or something.
???

Hutch · 05-10-2003, 07:52 PM

This is what I have found on an a/c equipped Truck.
The high speed fan relay is on the right side of the inside the cab heater box.
It is located near the passenger side cowl vent.
Behind the glovebox.
There is a black ground wire from the relay to the firewall that is about three inches long.
If the ground wire is broken or not making a good ground you will have the symptoms you described.
Also check the connector to the relay it self as it may need to be taken loose and reseated.
Also check the fuse panel for blown fuses and loose connections.

Have fun

jimfulco · 05-11-2003, 03:03 AM

Wiggle all the connectors. If it works then, you need to clean them.

05-10-2003, 04:50 PM	#1
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	Heater/AC blower question I have a question about the blower speeds on one of my K20s. A friend borrowed my manual so I can't rember how I fixed this on another truck. I can only get the blower to work on one of the switch settings (third one down). It will not work on high or low. Isn't there a rheostat or something in the system? Or do you think it is the switch itself? Thanks for your help. I figured this would be quicker than going to get my manual.

05-10-2003, 07:52 PM	#3
Hutch Registered User Join Date: Oct 2001 Location: Grapevine, Tx. Posts: 2,142	This is what I have found on an a/c equipped Truck. The high speed fan relay is on the right side of the inside the cab heater box. It is located near the passenger side cowl vent. Behind the glovebox. There is a black ground wire from the relay to the firewall that is about three inches long. If the ground wire is broken or not making a good ground you will have the symptoms you described. Also check the connector to the relay it self as it may need to be taken loose and reseated. Also check the fuse panel for blown fuses and loose connections. Have fun __________________ John Hutchison Grapevine,Texas 68 1/2 t swb 68 Mustang 69 Jaguar 71 1/2 t swb 88 Supra CompTs6m 93 Escort GT 2005 Corolla XRS

05-10-2003, 05:22 PM	#2
Dads72 Registered User Join Date: Nov 2002 Posts: 427	For what it's worth, I seem to recall that the high speed switch is by itself - maybe has it's own relay or something. ???

05-11-2003, 03:03 AM	#4
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Wiggle all the connectors. If it works then, you need to clean them.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.