a/c blower relay question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

19mike69 · 03-02-2003, 04:15 PM

im trying to pinpoint if the relay is bad or not....i tried to run a new ground as ive seen stated in other posts on here but it didnt help....i know the fan works on high because i ran a jumper from the battery to the fan and it works on high...then it took the plug off the back of the switch and jumped a wire from the brown to the other 3 terminals one at a time....2 would work,im assuming low and med.....but when i tried to jump to the orange wire(which runs from the back of the switch to the relay by itself) all it does is make the relay click.....does this mean the relay is bad?

Longhorn Man · 03-02-2003, 04:41 PM

Unplug the relay, and see if there is power from any other wire other than the orange one. If there is power at one of the others, then replace the relay.

19mike69 · 03-02-2003, 05:04 PM

you mean to unplug the plugs on top of the relay and then try it?....i dont quite follow what you are saying...

Longhorn Man · 03-02-2003, 05:20 PM

Yeah, unplug the harness, and use a test light or better yet, and volt tester/multimeter. check all the wires for power, you should have power at the one coming from the switch (if the switch is on high and the ignition is on) and then you'll have power at another wire. I can't see the colors on my pic, and I can't find my schematics, but I think there is a red, and orange, and black maybe.
If you have power at these wires, (2 of the 3) than you need a relay. If you have power at only the one wire coming from the switch, then you need to find out why you don't have power at two wires. (and confirm which one is supposed to be powered besides your orange one)

19mike69 · 03-02-2003, 05:26 PM

ok,thanks....ill see if i can do that....mine really doesnt look like yours though,does that matter?

Longhorn Man · 03-02-2003, 05:35 PM

Disregard the pic then...I might be thinking of something else.
But the troubleshooting remains the same.

19mike69 · 03-02-2003, 05:38 PM

ok,thanks again....ill have to go and try it out

19mike69 · 03-02-2003, 06:31 PM

well,it must be the relay.....mine has 2 plugs on it....one plug has 3 wires,and the other one has one wire....i unplugged the one with one wire(orange) and that wire goes it the switch and it still worked the same

jhow66 · 03-02-2003, 09:29 PM

Had same problem. From the relay on the heater box (look up between heater and kickpanel on pass. side) there is a wire that runs over to fuse panel.(should be a red or large orange wire) This wire was just unhooked on mine. (plugs into one of the slots on side of panel.) This wire sends 12 volts to the fan motor when the fan switch is in high postion. (fan switch in high engages relay) When fan switch is in low or med. the current flows from the fan switch(not from fuse panel wire) thru the resistor that is located in heater box air stream-then thru relay to fan. The wire coming from fuse panel should be hot at all times. Hope this helps.

mtdave2 · 03-02-2003, 09:53 PM

my bet is its the relay that set to the left of the glove box. If not there, its the rheostat in side the distribution box.

19mike69 · 03-02-2003, 09:56 PM

ill check that bigger orange wire that goes from the fuse box directly to the relay tomorrow.....but im thinking its the relay myself

03-02-2003, 04:15 PM	#1
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	a/c blower relay question im trying to pinpoint if the relay is bad or not....i tried to run a new ground as ive seen stated in other posts on here but it didnt help....i know the fan works on high because i ran a jumper from the battery to the fan and it works on high...then it took the plug off the back of the switch and jumped a wire from the brown to the other 3 terminals one at a time....2 would work,im assuming low and med.....but when i tried to jump to the orange wire(which runs from the back of the switch to the relay by itself) all it does is make the relay click.....does this mean the relay is bad?

03-02-2003, 09:29 PM	#9
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Had same problem. From the relay on the heater box (look up between heater and kickpanel on pass. side) there is a wire that runs over to fuse panel.(should be a red or large orange wire) This wire was just unhooked on mine. (plugs into one of the slots on side of panel.) This wire sends 12 volts to the fan motor when the fan switch is in high postion. (fan switch in high engages relay) When fan switch is in low or med. the current flows from the fan switch(not from fuse panel wire) thru the resistor that is located in heater box air stream-then thru relay to fan. The wire coming from fuse panel should be hot at all times. Hope this helps. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

03-02-2003, 09:53 PM	#10
mtdave2 newly minted old timer Join Date: Dec 1999 Location: Hudson WI Posts: 3,521	my bet is its the relay that set to the left of the glove box. If not there, its the rheostat in side the distribution box. __________________ ____________________________________________ 72 c20 longhorn 65k org miles and counting! 69 k10 Suburban

03-02-2003, 04:41 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Unplug the relay, and see if there is power from any other wire other than the orange one. If there is power at one of the others, then replace the relay.

03-02-2003, 05:04 PM	#3
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	you mean to unplug the plugs on top of the relay and then try it?....i dont quite follow what you are saying...

03-02-2003, 05:20 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Yeah, unplug the harness, and use a test light or better yet, and volt tester/multimeter. check all the wires for power, you should have power at the one coming from the switch (if the switch is on high and the ignition is on) and then you'll have power at another wire. I can't see the colors on my pic, and I can't find my schematics, but I think there is a red, and orange, and black maybe. If you have power at these wires, (2 of the 3) than you need a relay. If you have power at only the one wire coming from the switch, then you need to find out why you don't have power at two wires. (and confirm which one is supposed to be powered besides your orange one)

03-02-2003, 05:26 PM	#5
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	ok,thanks....ill see if i can do that....mine really doesnt look like yours though,does that matter?

03-02-2003, 05:35 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Disregard the pic then...I might be thinking of something else. But the troubleshooting remains the same.

03-02-2003, 05:38 PM	#7
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	ok,thanks again....ill have to go and try it out

03-02-2003, 06:31 PM	#8
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	well,it must be the relay.....mine has 2 plugs on it....one plug has 3 wires,and the other one has one wire....i unplugged the one with one wire(orange) and that wire goes it the switch and it still worked the same

03-02-2003, 09:56 PM	#11
19mike69 Registered User Join Date: Jul 2002 Location: pottsboro,tx Posts: 513	ill check that bigger orange wire that goes from the fuse box directly to the relay tomorrow.....but im thinking its the relay myself



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.