Heater Control Cables

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Moose Drool

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Brian
Truck Year
1984
Truck Model
K1500
Engine Size
350
My '84 GMC K1500 didn't come with a heat only control unit. Does anyone have pictures that show which cables go where on the unit?

Thanks in advance.
 

Dmack

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I can post some tomorrow if no one does before then. My 83 was originally ac, but it was gutted. I just got a complete assembly from a 73 (control panel, cables, inside airbox assembly all connected, and the fan and metal housing from the engine compartment) and it bolted in easily.
 

Moose Drool

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Engine Size
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I can post some tomorrow if no one does before then. My 83 was originally ac, but it was gutted. I just got a complete assembly from a 73 (control panel, cables, inside airbox assembly all connected, and the fan and metal housing from the engine compartment) and it bolted in easily.

Thanks I would appreciate some pics. Mine came with an a/c control panel, without the cables hooked up. The truck doesn't even have a/c lol
 

Dmack

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Here is the non ac setup I have. If you are going to use the a.c. panel and inside box, you're will be significantly different. I believe they are controlled by vacuum lines. There were a couple of recent threads on them I will try to find and post a link. The top control cable controls the right hand arm.
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Moose Drool

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Southern Oregon
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Brian
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1984
Truck Model
K1500
Engine Size
350
Here is the non ac setup I have. If you are going to use the a.c. panel and inside box, you're will be significantly different. I believe they are controlled by vacuum lines. There were a couple of recent threads on them I will try to find and post a link. The top control cable controls the right hand arm.
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I'm putting in a heater only control. The a/c unit is up for sale.
 

Dmack

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1983
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K20
Engine Size
350
It is a simple swap. Just get the entire heat only system and it just bolts in. When I got mine, I left the heater controls attached to the inside heater box. No losing parts. Then just pull the fan box from the engine compartment with the wiring and you are golden.

A couple of suggestions.

Get a new heater core. Cheap insurance.

Be sure to get the factory heater box wiring loom. It comes from the fan switch, through the firewall in a large rubber plug/grommet, then ends at the fan motor. Flat multicolor wire that looks like trailer wire.

Cut a hole in the firewall under the new heater box housing (covered by the housing when installed) , right side under the resistor about 3" x5". Since you will have made a block off plate for the old ac system holes in the firewall, your heater needs a place for air to enter the system. Otherwise, you get lots of fan noise but no air movement (ask me how I know).
 
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Dmack

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Engine Size
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Here is a pic of the block off plate for the ac holes.

The blue square is approximately where you would cut the air supply hole in the firewall.

The pink is where the factory wiring harness comes through. Get the entire harness from the switch to the fan motor.

The green is a bastard of a bolt that I would recommend leaving out when installing the fan box. It is easy to install with the inner fender removed. However, if you ever needed to remove the housing, say to swap out the heater core, good luck getting to it with the inner fender installed.
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bigLhr

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Westover
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Larry
Truck Year
1976
Truck Model
k10 1500
Engine Size
350
Here is the non ac setup I have. If you are going to use the a.c. panel and inside box, you're will be significantly different. I believe they are controlled by vacuum lines. There were a couple of recent threads on them I will try to find and post a link. The top control cable controls the right hand arm.
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Did the right side door open only slightly? My heater control lever broke from trying to move it to defrost. I don't know what the right side window does?? I just really hate to put all back together with that door only moving slightly. Thanks
 
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Dmack

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Engine Size
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Sorry, it's been long enough since I did the conversion I don't recall. Maybe someone else will chime in.
 

RanchWelder

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Decided to fabricate my heater/blower under the dash.
No wet electrical, more firewall space under the hood.

Drawing air from the ankle vent port that goes through the fender well beside the right fender kick panel and around the firewall for air source. I have it so I can block it off and recirculate warm inside air for the winter.

Bought a new OEM core and used it inside my custom bent and riveted plenum.

Blower sticks out close to the stock hunk of plastic duct did, without all the crap and flippers and vacuum systems. It's all gone. Single pull switch, no temperature controls or routing of air.
Simple.

Used a small diameter tire tube to run as a duct between my custom housing and the stock plastic air duct to the defrosters.

There's a small diameter hole with a metal slide cover over the front side now, that can be opened or closed to send warm air to the passenger's side, (not in the pictures).

Usually get by with 1400 gram thermal insulated boots and use it for the windshield, most of the winter.

Installed a 5/8 inch ball valve in the hose coming from the cylinder head/manifold port, so the water does not circulate with hot water during the summer, into the cab or defogger/defroster/heater.

Just cabin air during the warmer months for a clear windshield. Works OK. No issues.

The blower snail is from an old famous wood stove company, that had a blown electric motor.

Carved out the same shape as the GM Blower from my truck and mounted it to run off the hot heater relay with a fuse, same as normal. Centered over the intake housing, equal spaced for good flow.

The heater resistor coils had to go, so located a semi-truck dash pull switch with a single resister coil mounted in the switch. It has Off/Hi/Off. Very simple. It required extra electrical tape to cover the exposed wiring, however, you cannot wrap the resistor coil. It gets hot.

It's loud from the volume of air it moves and cleans the snow and ice in a few minutes while the truck warms up. Usually have to open the windows with winter clothes on, so I don't sweat to death with it running.

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Here's where it meets with the plastic defroster duct:
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Here's the dash, (every gauge was bought slightly blem for less than 1/2 price or lower. Took a long time to collect them all at an extreme discount):
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The empty hole in the switch panel got the pull switch.
Eventually it will all get aluminum down below and then carefully covered in oiled Elk Skin up top and screwed panels below.

Same with the door panels.
Stainless plate where the plastic plate/door pull used to be, over padded/oiled Elk Skin custom panels.

Not as classy as a restoration job.
It works and it's all made from scrap and stock parts, except the switch and the new core.

If you look close you'll see the small rubber tubing that cools the motor by drawing cold air from the front of the snail case, before it gets hot from the core.

2nd picture down, to the right of the snail box is directly pointed to the fresh air intake, where the passenger ankle vent used to have a flapper and a pull lever under the dash.

The flipper still works. Put small square screen mesh over the intake so small critters and cat toys don't get pulled into the Vortex. The Bat Cat rides beside me a lot.

The blower squirrel cage is the same one from either unit that works for your application.

Re-used the GM cage, so I had to bend the intake custom with a peen hammer to feed the cage and create a strong vortex.

At the right angle, there's plenty of leg room.

If you don't like the conversation coming from the passenger seat, it's easy to run it and keep saying HUH?

What you say?

The fat zip tie over the top of the blower is holding the core to a 1/4" inner tube rubber vibration damper.
All the gaskets to the blower and motor are made from used inner tube, as well.
It's glued to the metal, holding the core from rubbing or breaking loose.

The inner tube duct is ugly.

Could have bought two 3 inch aluminum duct flex hoses and used the inner tube up under the dash at the transition, to make it look nicer. It's a work in motion.

If it requires changing out, it's just 6 rivets through the firewall to drill out and slip the latch on the fat zip tie to install a new core.

Proper coolant and de-ionized water, should be good for another 37 years?
Lot less complicated.

There was no way I was spending $380.00 on the factory resto units or the flimsy under the dash aftermarket stuff I looked at. Plastic housing and flimsy dual squirrel cages with cheap ball bearings.

The really nice stuff in the picture from the gentleman's post, is sweet and above my pay grade.

After having no heater for 1/2 a winter, it sure was nice to have it working again.
 
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