AC Resistor wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Hardway · 11-14-2007, 10:33 PM

Ive run in to another snag on installing the new Painless harness into my '72 SWB Chevy. When I was extracting the harness from the cab there were 4 wires going in to the AC box under the dash facing towards the firewall, a med. blue wire, light blue wire, and 2 yellow wires through a sealing type grommet. The original harness was hacked to death so I just left some wiring hanging and cut it, figured I would deal with it later. Well now it is later and according to the AC harness I got from Painless the wiring go to a resistor inside the box. My question is, how deep is the resistor in the box? I can not feel it by sticking my fingers through the hole where the wires come out. Do I have to take the entire AC box apart? Also, the harness has a 3 wire connector with 1 wire for each color as above. If I were to cut the connector off and hard wire it, what do I do with the extra yellow wire that is left? As always everyones assistance is greatly appreciated.

Hardway · 11-22-2007, 09:37 PM

Anyone at all?

ccd3 · 11-22-2007, 10:20 PM

It's been awhile- but I remember running into the same problem-

poke around some more- you should be able to get in there without taking anything apart. It's not as deep as you think it is.

Good Luck

dwaite72lnghrn · 11-23-2007, 06:10 AM

The "resistors" are 2 coils of resistive wire attached to the spade connectors. I don't have a picture of them now. They change the resistance depending on the the heat or cooling on them. They are about 1/2" long for 1 and 3/8" long on the other 1, They only stick down into the plenum about 3/4".

Hardway · 11-26-2007, 05:33 PM

Do you know what direction in the under dash box they are located? I felt around inside and have still been unable to find them.

stope4 · 11-26-2007, 06:00 PM

If I remember there's a grommet where the wires go through the box. Either pull or push the grommet from around the box and then pull the cut wires and see if you can get the connector off of the resistor. It's preferable to pull the grommet away from the box but either will work. Once you remove the wires see if you can use a long needle nose pliers and reconnect through the hole. If this doesn't work, just drop the box, it's not that difficult.

dwaite72lnghrn · 12-04-2007, 02:34 PM

I almost had the truck go up in flames the other night. A mouse built a home in the ac box. So here are some pictures of the resistors.
By the way I had taken out my extinguisher and flash light, So I am reaching in through the bottom vent hole trying to pull out smoldering leaves and such looking at the glow to go away, The whole time my wife is saying use your extinguisher. To which I reply I took it out!!! Response was something like dummy, But I couldn't hear over my own cursing my own stupidity.
So you benefit as I take it apart to make sure all the stuff is out of there.

Hardway · 12-15-2007, 05:34 AM

Thank you for the picutres! They truly help. Now I can finally finish this wiring project.

sneakysnake · 12-15-2007, 05:45 AM

another pic

11-14-2007, 10:33 PM	#1
Hardway Registered User Join Date: May 2007 Location: Cedar Park, TX USA Posts: 52	AC Resistor wiring Ive run in to another snag on installing the new Painless harness into my '72 SWB Chevy. When I was extracting the harness from the cab there were 4 wires going in to the AC box under the dash facing towards the firewall, a med. blue wire, light blue wire, and 2 yellow wires through a sealing type grommet. The original harness was hacked to death so I just left some wiring hanging and cut it, figured I would deal with it later. Well now it is later and according to the AC harness I got from Painless the wiring go to a resistor inside the box. My question is, how deep is the resistor in the box? I can not feel it by sticking my fingers through the hole where the wires come out. Do I have to take the entire AC box apart? Also, the harness has a 3 wire connector with 1 wire for each color as above. If I were to cut the connector off and hard wire it, what do I do with the extra yellow wire that is left? As always everyones assistance is greatly appreciated. __________________ Jeff's Current Vehicles: 1989 Turbo Trans Am Pacecar "Life is like racing, it goes by fast and has many turns"

11-22-2007, 09:37 PM	#2
Hardway Registered User Join Date: May 2007 Location: Cedar Park, TX USA Posts: 52	Re: AC Resistor wiring Anyone at all? __________________ Jeff's Current Vehicles: 1989 Turbo Trans Am Pacecar "Life is like racing, it goes by fast and has many turns"

11-22-2007, 10:20 PM	#3
ccd3 Registered User Join Date: Mar 2007 Location: Austin, TX Posts: 93	Re: AC Resistor wiring It's been awhile- but I remember running into the same problem- poke around some more- you should be able to get in there without taking anything apart. It's not as deep as you think it is. Good Luck

11-23-2007, 06:10 AM	#4
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	Re: AC Resistor wiring The "resistors" are 2 coils of resistive wire attached to the spade connectors. I don't have a picture of them now. They change the resistance depending on the the heat or cooling on them. They are about 1/2" long for 1 and 3/8" long on the other 1, They only stick down into the plenum about 3/4". __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

11-26-2007, 05:33 PM	#5
Hardway Registered User Join Date: May 2007 Location: Cedar Park, TX USA Posts: 52	Re: AC Resistor wiring Do you know what direction in the under dash box they are located? I felt around inside and have still been unable to find them. __________________ Jeff's Current Vehicles: 1989 Turbo Trans Am Pacecar "Life is like racing, it goes by fast and has many turns"

11-26-2007, 06:00 PM	#6
stope4 Registered User Join Date: Jan 2006 Location: Houston Posts: 434	Re: AC Resistor wiring If I remember there's a grommet where the wires go through the box. Either pull or push the grommet from around the box and then pull the cut wires and see if you can get the connector off of the resistor. It's preferable to pull the grommet away from the box but either will work. Once you remove the wires see if you can use a long needle nose pliers and reconnect through the hole. If this doesn't work, just drop the box, it's not that difficult.

12-04-2007, 02:34 PM	#7
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	Re: AC Resistor wiring I almost had the truck go up in flames the other night. A mouse built a home in the ac box. So here are some pictures of the resistors. By the way I had taken out my extinguisher and flash light, So I am reaching in through the bottom vent hole trying to pull out smoldering leaves and such looking at the glow to go away, The whole time my wife is saying use your extinguisher. To which I reply I took it out!!! Response was something like dummy, But I couldn't hear over my own cursing my own stupidity. So you benefit as I take it apart to make sure all the stuff is out of there. Attached Images __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

12-15-2007, 05:34 AM	#8
Hardway Registered User Join Date: May 2007 Location: Cedar Park, TX USA Posts: 52	Re: AC Resistor wiring Thank you for the picutres! They truly help. Now I can finally finish this wiring project. __________________ Jeff's Current Vehicles: 1989 Turbo Trans Am Pacecar "Life is like racing, it goes by fast and has many turns"

12-15-2007, 05:45 AM	#9
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: AC Resistor wiring another pic Attached Images



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