Non AC truck. Should the dial slide all the way to cool?

[MisterB]

My temp slider stops right in the middle. I can slide it all the way to the right and it gets hotter and hotter as you get all the way to the right. The reverse happens and it gets cooler as you get towards the center and it stops and won't go any further. Should I be able to slide it all the way to the left?

You must be registered for see images attach

Sent from my SM-N975U1 using Tapatalk

 

[eskimomann209]

Yes
Check cable for damage or binding

 

[75gmck25]

The cable runs across behind the dash to a temperature/blend door lever that is on the plenum behind the glove box. If you remove the glove box door you can see the top of the plenum, and watch the lever move back and forth. There is also a adjuster with a set screw to adjust the door for full travel.

On the face of the HVAC plenum behind the glove box there is a plastic cover plate held on with a few screws. If you remove it you can see the blend door inside and watch it move. Its very common that something has fallen down the defroster vent and is inside the plenum blocking the door movement. Pens, pencils and small bolts are are a favorite.

Bruce

 

[MisterB]

The cable runs across behind the dash to a temperature/blend door lever that is on the plenum behind the glove box. If you remove the glove box door you can see the top of the plenum, and watch the lever move back and forth. There is also a adjuster with a set screw to adjust the door for full travel.

On the face of the HVAC plenum behind the glove box there is a plastic cover plate held on with a few screws. If you remove it you can see the blend door inside and watch it move. Its very common that something has fallen down the defroster vent and is inside the plenum blocking the door movement. Pens, pencils and small bolts are are a favorite.

Bruce

I lubed the cables you see at the top of the Pic. It's still not allowing full travel. Where is the plastic cover plate you're talking about? Can you point to it in my picture?

You must be registered for see images attach

Sent from my SM-N975U1 using Tapatalk

 

[dvdswan]

Your cable is probably misadjusted. I don't remember which one is the diverter for heater/defrost or temperature. Look at the diverters then slide the temp in the direction you can move it and see which door has moved. Take out the screw that holds that cable and see if the door has more movement in the direction you had originally moved it. If it does then adjust as required.

Be sure to measure the door direction in both ways.

 

[MisterB]

Your cable is probably misadjusted. I don't remember which one is the diverter for heater/defrost or temperature. Look at the diverters then slide the temp in the direction you can move it and see which door has moved. Take out the screw that holds that cable and see if the door has more movement in the direction you had originally moved it. If it does then adjust as required.

Be sure to measure the door direction in both ways.

I was starting to wonder the same thing. Does that mean when the control is in the middle, in reality it's as if it is all the way to the left?

How do I adjust the cable?

Sent from my SM-N975U1 using Tapatalk

 

[dvdswan]

I don't exactly know the book procedure. As I said, find which one of the cables adjust the temp door. Then figure out which direction is hot and which is cold. Cold should close the door from the heater core. The cable will be all the way extended or all the in. Place the loop hook on the door actuator and bolt the cable down. Verify the function. Done.

Note: I would verify that the lever mechanism in the dash is working properly first. I may be loose there.

Here is a link to the service manuals.... https://www.gmsquarebody.com/threads/1973-1991-service-manuals.14499/

It should have a section to tell you how to adjust the cables.

 

[chengny]

I was starting to wonder the same thing. Does that mean when the control is in the middle, in reality it's as if it is all the way to the left?

How do I adjust the cable?

Sent from my SM-N975U1 using Tapatalk

From the 1980 Service Manual:

You must be registered for see images attach

 

[MisterB]

I loosened the bolt, moved the lever all the way to the left and held it there while tightening it down. The lever moves past half way now, but only 3/4 of the way

Sent from my SM-N975U1 using Tapatalk

 

[AuroraGirl]

Sounds like maybe a rusted cable or binding maybe?

 

[Chevyguy]

Sounds like maybe a rusted cable or binding maybe?

Or a critter nest inside by that diverter door.

Clayton

Sent from my LM-V350 using Tapatalk

 

[MisterB]

Or a critter nest inside by that diverter door.

Clayton

Sent from my LM-V350 using Tapatalk

I'm just gonna pull the box and take a look.

Sent from my SM-N975U1 using Tapatalk

 

[MisterB]

OK, I decided it take the box out. It's a little involved because the heater core hoses need to be removed and there are bolts inside the truck and inside the engine that need to be undone. Of course the cables need to be removed too.

Guess what I found inside the box that was keeping the door from moving all the way? Let's just say I have another wrench today that I didn't have yesterday [emoji1787]

While I was in there, I put in a new heater core and all new hoses and hose clamps.

Problem solved

You must be registered for see images attach

Sent from my SM-N975U1 using Tapatalk

 

[Chevyguy]

Good job, I just replaced my heater core. Did you replace the foam weatherstripping wherever you had a duct connection?. I used 1/4 inch window weatherstripping tape from Home Depot and it worked great. No leaks.

Clayton

Sent from my LM-V350 using Tapatalk

 

[MisterB]

Good job, I just replaced my heater core. Did you replace the foam weatherstripping wherever you had a duct connection?. I used 1/4 inch window weatherstripping tape from Home Depot and it worked great. No leaks.

Clayton

Sent from my LM-V350 using Tapatalk

Na, I just reused that rubber strip it had.

Sent from my SM-T720 using Tapatalk