Under dash wiring help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

k5hart · 11-29-2010, 11:00 PM

Could someone help me understand what these wires should be doing??

I believe the Red is going to the cig lighter, the Orange is going to the blower motor relay, and the grey is for lighting somewhere? Is something supposed to be plugged in a the fuse panel?

This is on a 1972 blazer with A/C.

Thanks!

ls1nova71 · 11-29-2010, 11:59 PM

The red wire for the cigarette lighter plugs into the fuse box in a spot labled "cig", the gray wire is for the lights in the heater controls and the extra plug coming off of it would be used for the light in the shift indicator if you had a tilt column, it plugs in a spot on the fuse box labled "clstr feed". The orange wire for the blower motor I believe plugs in the "ign unfused" spot, but I'd have to look at my truck to be positive.

k5hart · 11-30-2010, 08:26 AM

Thanks lsnova71. I thought that was the case on all but the Orange wire. The connector on the orange wire isn't designed to plug into the fuse panel. It can however plug into one of the connectors on the red wire. This is my biggest question actually. I'm trying to fix my hign fan speed and I am not getting power at the orange wire. Just wanted to make sure I'm right before plugging wires in randomly. If this is right my next problem will be fixing my cig lighter feed on the fuse panel. PO has burned the connector up.

TobyArnot · 11-30-2010, 09:35 AM

If that orange wire is paired with a white wire, it's likely for the dome light.

**70cst** · 11-30-2010, 09:40 AM

You all are good!!!

KEL · 11-30-2010, 09:47 AM

Quote:

Originally Posted by k5hart

Thanks lsnova71. I thought that was the case on all but the Orange wire. The connector on the orange wire isn't designed to plug into the fuse panel. It can however plug into one of the connectors on the red wire. This is my biggest question actually. I'm trying to fix my hign fan speed and I am not getting power at the orange wire. Just wanted to make sure I'm right before plugging wires in randomly. If this is right my next problem will be fixing my cig lighter feed on the fuse panel. PO has burned the connector up.

your picture looks exactly like under my dash, and I've wondered the same things. Also, I have no high speed on my fan either ! When you get it all
sorted out, will you let me know ?
Thanks

k5hart · 12-01-2010, 09:32 AM

Orange wire is definetly going over to the blower motor relay. I don't think it's the dome wire. The grey wire may be though. I am still a little confused on what's supposed to be. The Red wire is definetly going to the cigarette lighter and the orange connector fits right into one of the red connectors. Would they have pulled power for the high speed blower from the cigarette lighter?? Seems weird to me but possible I guess.

Anyone with an original truck out there that could check this? I've been going through the assembly manual but not getting a lot of clarification there.

k5hart · 12-01-2010, 12:44 PM

Based on this post I think my idea is correct. The Orange plugs into the second jumper off the Red wire which plugs into the Cig port on the fuse panel. Funny how I've missed that on the diagram everytime I looked at it. I think I didn't believe it.

http://67-72chevytrucks.com/vboard/s...ghlight=blower

I'll have to figure out how to try this out. I wish my Cig connector wasn't burned off. I'll start a new post asking how to fix that I guess.

**Classic Heartbeat** · 12-01-2010, 02:41 PM

Red wire plugs into the CIG. plug.
Gray wire plugs into CLSTR FEED plug.
Do the gray wire and orange wire run together in the harness?
If so the gray wire is for the light bulbs in the heater control, and the orange wire is the main power wire for the heater/AC. There should be a brown #10 wire that plugs into it. WES

k5hart · 12-01-2010, 03:38 PM

Quote:

Originally Posted by Classic Heartbeat

Do the gray wire and orange wire run together in the harness?

Yes they do.

Quote:

Originally Posted by Classic Heartbeat

If so the gray wire is for the light bulbs in the heater control, and the orange wire is the main power wire for the heater/AC. There should be a brown #10 wire that plugs into it. WES

Maybe this is why only one light works on the heater control.
Where should the brown #10 plug in??

FYI. Heater core worked great. Thanks! This has been an adventure getting everything put back right and working.

**Classic Heartbeat** · 12-01-2010, 05:59 PM

I am glad that the heater core worked out for you. I try to keep the highest quality parts here in stock and I have used that brand befor myself. The brown wire is a part of the main underdash harness. You probably will have to search it out. You might check the light bulbs in your control while you are under the dash. WES

11-29-2010, 11:59 PM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: Under dash wiring help The red wire for the cigarette lighter plugs into the fuse box in a spot labled "cig", the gray wire is for the lights in the heater controls and the extra plug coming off of it would be used for the light in the shift indicator if you had a tilt column, it plugs in a spot on the fuse box labled "clstr feed". The orange wire for the blower motor I believe plugs in the "ign unfused" spot, but I'd have to look at my truck to be positive.

11-30-2010, 08:26 AM	#3
k5hart Registered User Join Date: Nov 2002 Location: Charleston, South Carolina Posts: 1,370	Re: Under dash wiring help Thanks lsnova71. I thought that was the case on all but the Orange wire. The connector on the orange wire isn't designed to plug into the fuse panel. It can however plug into one of the connectors on the red wire. This is my biggest question actually. I'm trying to fix my hign fan speed and I am not getting power at the orange wire. Just wanted to make sure I'm right before plugging wires in randomly. If this is right my next problem will be fixing my cig lighter feed on the fuse panel. PO has burned the connector up. __________________ 2006 Silverado CCSB, 1939 Ford Sedan, 1962 BelAir Wagon, 1976 Vega Panel Charleston, South Carolina

11-30-2010, 09:35 AM	#4
TobyArnot Quit if it's not FUN!!! Join Date: Jul 2010 Location: Indian Trail, N.C, Posts: 864	Re: Under dash wiring help If that orange wire is paired with a white wire, it's likely for the dome light. Last edited by TobyArnot; 11-30-2010 at 09:35 AM.

11-30-2010, 09:40 AM	#5
70cst Senior Member Join Date: Feb 2001 Location: New Madison, Ohio Posts: 21,365	Re: Under dash wiring help *You all are good!!!* __________________ A husband can be right...or...A husband can be happy. 67-72 Chevy and GMC Trucks...The Classic Truck for the Classic Folk. 1970 CST Two tone green, 402BB, 400 Automatic, Tach, Buckets, AC, AM-FM, Tilt, GM CB, GM 8 Tract, LWB, etc JOHN 17:3...The better side of "LIFE" Remember: Everyday is a good day...Some are just gooder!

12-01-2010, 09:32 AM	#7
k5hart Registered User Join Date: Nov 2002 Location: Charleston, South Carolina Posts: 1,370	Re: Under dash wiring help Orange wire is definetly going over to the blower motor relay. I don't think it's the dome wire. The grey wire may be though. I am still a little confused on what's supposed to be. The Red wire is definetly going to the cigarette lighter and the orange connector fits right into one of the red connectors. Would they have pulled power for the high speed blower from the cigarette lighter?? Seems weird to me but possible I guess. Anyone with an original truck out there that could check this? I've been going through the assembly manual but not getting a lot of clarification there. __________________ 2006 Silverado CCSB, 1939 Ford Sedan, 1962 BelAir Wagon, 1976 Vega Panel Charleston, South Carolina

11-29-2010, 11:00 PM	#1
k5hart Registered User Join Date: Nov 2002 Location: Charleston, South Carolina Posts: 1,370	Under dash wiring help Could someone help me understand what these wires should be doing?? I believe the Red is going to the cig lighter, the Orange is going to the blower motor relay, and the grey is for lighting somewhere? Is something supposed to be plugged in a the fuse panel? This is on a 1972 blazer with A/C. Thanks! __________________ 2006 Silverado CCSB, 1939 Ford Sedan, 1962 BelAir Wagon, 1976 Vega Panel Charleston, South Carolina

12-01-2010, 12:44 PM	#8
k5hart Registered User Join Date: Nov 2002 Location: Charleston, South Carolina Posts: 1,370	Re: Under dash wiring help Based on this post I think my idea is correct. The Orange plugs into the second jumper off the Red wire which plugs into the Cig port on the fuse panel. Funny how I've missed that on the diagram everytime I looked at it. I think I didn't believe it. http://67-72chevytrucks.com/vboard/s...ghlight=blower I'll have to figure out how to try this out. I wish my Cig connector wasn't burned off. I'll start a new post asking how to fix that I guess. __________________ 2006 Silverado CCSB, 1939 Ford Sedan, 1962 BelAir Wagon, 1976 Vega Panel Charleston, South Carolina

12-01-2010, 02:41 PM	#9
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Re: Under dash wiring help Red wire plugs into the CIG. plug. Gray wire plugs into CLSTR FEED plug. Do the gray wire and orange wire run together in the harness? If so the gray wire is for the light bulbs in the heater control, and the orange wire is the main power wire for the heater/AC. There should be a brown #10 wire that plugs into it. WES __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

12-01-2010, 05:59 PM	#11
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Re: Under dash wiring help I am glad that the heater core worked out for you. I try to keep the highest quality parts here in stock and I have used that brand befor myself. The brown wire is a part of the main underdash harness. You probably will have to search it out. You might check the light bulbs in your control while you are under the dash. WES __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys



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