Climate control, vents blow hot air

[donalds]

Because that's at least a 1/2 day (probably more like a full day) of my life I'd never get back. Besides, if you go that route you're almost guarantied to have a new problem that you created by pinching/pulling wires or vacuum hoses reinstalling the dash. I'm usually a proponent of doing things the "right way", but if I have a broken blend door I'm cutting the heater box with my Dremel. If you have a leaking heater core, that's a different story.

With the age of these trucks and the brittleness of the plastics and wires, I wouldn't do the dash removal. I think it quotes as a 16 hour job to fix the blend door that way? I may be wrong though. You have to figure, in that video he started with a stripped dash. The blend door "surgery" with the hacking of the heater bx can take 45 minutes to 3 hours.

I'm not saying I wouldn't cut the box but I'm ocd so I would probably do both heater core and blend door at the same time if either when bad
Never thought of the plastic being brittle
I haven't had that experience on my truck
But I understand that said I'd pull the dash over a weekend but I am meticulous so I probably wouldn't break things pulling it but I understand that to
I figured I'd put the info out there
If I did cut the box it would have to be done in a very clean way or it would bug the he'll out of me

 

[John Quinn]

To index the actuator to the door, I place the actuator where it goes and run the temp UP and DN. At some point the "D" shaped post on the actuator should line up with the door and drop in. Note, getting the actuator to spin may require first running the EATC self test to clear error codes.

 

[John Quinn]

One more question, if I may.
There is a vacuum valve on the heater/water line under the hood. There is a nipple on it, but no vacuum line connected to it, and no wires.
It something missing? And if so, where should it be attached for a vacuum source?

 

[donalds]

One more question, if I may.
There is a vacuum valve on the heater/water line under the hood. There is a nipple on it, but no vacuum line connected to it, and no wires.
It something missing? And if so, where should it be attached for a vacuum source?

Gray vacuum line probably broken or just hanging there goes to the nipple on the heater control valve

 

[John Quinn]

Where would I look for the other end of it?

 

[donalds]

Somewhere right there by the fire wall

 

[koda2000]

You can start looking for broken vacuum lines down where the vacuum lines come in/and go out of the vacuum reserve ball, which is located in front of the right front tire, on top of the plastic inner fender. You can't really see the ball, but you should see several plastic vacuum lines in that area. One goes back to the intake manifold and the other supplies vacuum to the HVAC controls and the heater control valve.

Note: IMO the heater control valve probably isn't your issue, though it has to be connected to function, however in pure A/C mode the heater core is closed off from the A/C side evaporator compartment (unless you're blending some heat with your A/C). In the MAX A/C setting the heater control valve is closed, preventing hot coolant from flowing through the heater core and the system is also closed off to outside air.

Your issue may be a bad blend door actuator or a broken blend door. Both are common points of failure on these trucks.

 

[donalds]

Great info koda

I think I may have removed the air box to replace the vacuum reservoir at one time may give a good view
And that air box is cake to remove

 

[koda2000]

Great info koda

I think I may have removed the air box to replace the vacuum reservoir at one time may give a good view
And that air box is cake to remove

I usually just drop the front of the right side plastic inner fender to get access to the vacuum ball, which is easy to do. IDK if removing the air filter box would work. Maybe. The ball is mounted to the plastic inner fender with just 2 bolts.

 

[donalds]

Yes sir I ment to get a good look but the inner fender is good to mine was crushed with a blown tire took out the inner fender and the ball 25$ later at the jy

 

[John Quinn]

A new issue has come up. While performing the self test on the control (floor+off) the floor button "collapsed" and doesn't function. On top of that, I'm no longer getting 12V at the A/C pump.
So far, I've had the freon drained, vacuum tested the system and refilled. The high low pressure valves were leaking and replaced. The air blew cold for about two days and quit.
If I hot wire the pump, the air is frigid cold. Tried jumping the low pressure switch, no dice. I can't locate the A/C relay as the manual is somewhat ambiguous.
Also checked the wiring to the pump, checked out ok according to the tech
Could the collapsed "floor" button be the problem with the voltage? Everything was working except the floor function, and there (formerly) was 12.8V at the pump.
(Sigh)
Happy Friday the 13th.

 

[koda2000]

I don't know about collapsed EATC button, but I guess it's possible something in the EATC got shorted out. In any event you're going to have to get a replacement EATC module or perhaps send your's out for repair ($100 + shipping both ways). I'd look for a used EATC module on eBay or maybe the JY. It's also possible that your EATC is causing intermittent compressor engagement. There is a small relay inside the EATC module that turns the compressor on/off. I've read multiple threads where this relay fails or breaks it's solder joints and then the compressor clutch sometimes does not receive the signal to turn on..

So, looking for a good used EATC module may fix both your issues, but that doesn't explain why you get hot/heated air when you EATC has been set to 60 degrees/A/C MAX. Only a broken blend door can cause that.

 

[John Quinn]

I've done the following:
Had both high and low pressure schrader valves replaced, replaced freon and oil by a professional.
I've tested the high and low pressure switches, both connect on the ohm meter while the pump is jumped and running. Both high and low pressure connectors show 12 plus volts under the same conditions.
Fuses are all good.
Now the questions.
1)Is there a relay for the A/C clutch in the Power Center under the hood? I can't locate it, the manual is ambiguous at best. Someone mentioned swapping out the horn relay with it,, so I assumed it's one that size and swapped all three back and forth. No change.
2) I removed the EATC (A/C control). The block of vacuum hoses has a black one in the top/middle with no hose connected to it. There is a port on the EATC behind it, though. I looked in the harness for a loose hose, nothing there. I assume that this is normal, am I correct?
3 ) I know that I have either a door actuator or door situation. Would this affect the voltage to the A/C clutch?
4) The engine rpm's did not increase at any time during all this testing. Is this a clue to anything?
Whew!
I'm leaving the dash apart until I hear from one of you kind gentlemen. I'll cap the vacuum lines with duct tape or something in the mean time and sing to myself without the radio, lol.
Thank you all in advance.

 

[John Quinn]

I found it. I read a couple of other threads and decided to take out the EATC.
Lo and behold, a factory cold solder joint on the relay. Explains why the A/C solenoid clicked when I thumped the dash one time.
It runs colder than a morgue now.
Thank you to all that contributed comments!!
Next stop the door actuator.