A/C Heater Control Assembly 1984 F-250

[mankypro]

So, I'm still trouble shooting my heater vents. Trying to figure out why no matter position in the vent/heater settings I get feet/vent and never defrost.

I have factory a/c. I have the control assembly that has the vacuum harness popping out the right side of it. I've tested for vacuum it's there and it's strong.

One thing I have noticed is that the compressor clicks on before the slider even reaches defrost - it kicks on on the floor setting which is the second to last on the passenger side of the slider.

Looking at the vacuum harness it seems like there are nipples on it that aren't connected, but no hoses dangling about.

Any ideas on how to go about trouble shooting this?

 

[NCheek]

Best bet will be if someone can break out some vacuum diagrams and then you can make sure that you have everything hooked up.

 

[mankypro]

it sucks that you have to completely disconnect everything to get the controller out of the dash. I think the vacuum lines use a connector now that I'm looking at the diagrams. I bet you the switch or the door hinge is fraked.

 

[NCheek]

I thought you fixed the door hinge a while back?

 

[mankypro]

nope, I don't even know where to look for the hinge - is it in the plenum to the driver's side from the core?

I can see the silver can extending and contracting the tab when I switch around on the vent switch so it's working - just wonder if the door is jammed or broken...

I thought you fixed the door hinge a while back?

 

[riphip]

Ford part# E0TZ-18A361-A Control

If you remove the heater cover inside, you should be able to see the panel door on the left side of the ventilator box. Vertical hinged door -- this is controlled by the vacuum accuator motor at the bottom behind the ashtray area. You can run your engine and switch from vent to floor or max air to defrost and see it open or close from left to right. There should be no space on the left side of the panel door towards the vacuum accuator motor.

Hinge does not look like a normal hinge. Whole piece is plastic & the hinge is formed into the piece. You will see 2 steel rivets on the lower part and 2 bolt heads on the upper part. (This is with the heater cover removed)

Rick

 

[NCheek]

Hate to say it, but the dash has to open up one more time. Remove the dash pad and take the passenger side vent ducting out, you will be glad you did.

I have heard of some using an actual hinge, but when I did mine, I had to use a little ingenuity. I cut a strip of inner-tube and used 1/4" nuts and bolts to fasten it to the "door side" and the "duct side".

The worst part of the whole deal was re-installation because the door seals against the inside of the duct that it mounts in and it makes it terribly difficult to hold the nut on the backside when you are trying to mount the door.

I think you can still get the OEM piece from ford, but I dunno about the cost, and in time (probably another 20-25 years) it will fail again. Not saying that mine won't fail either...

If this doesn't make sense, I can try to explain in more detail.

 

[MIDNIGHT RIDER]

The door may very well be his problem, but it shouldn't have any effect on the A/C compressor kicking in and out at places on the switch that it shouldn't.

I still think it is the vacuum-switch.

Then again, I could be wrong.

 

[NCheek]

The door may very well be his problem, but it shouldn't have any effect on the A/C compressor kicking in and out at places on the switch that it shouldn't.

I still think it is the vacuum-switch.

Then again, I could be wrong.

Now that I slow down and think about it, vacuum controls not working correctly + ac compressor engaging at improper selection leans toward the selector switch.

 

[mankypro]

anyone have a part number for the vacuum selector? The number I got off of it doesn't cross reference with anything at the local parts stores. Looks like I need to call Ford.

 

[MIDNIGHT RIDER]

The last one of those I bought came from Advance, years ago, for about $16.

Surprisingly, I have just searched Advance, NAPA, Rock Auto, and found NO MENTION of the vacuum-selector switch.

I found it listed at O'Reilly's, but no price and it said "special order item".


I find this hard to fathom, as those switches are notorious for going bad and should be common as fleas on a dog.

Nearly every A/C-equipped vehicle employs a vacuum-selector switch contained within the heater/A-C control mechanism and it is not at all un-common to have to replace them.




If they are gonna be that hard to find, then I guess I had better find myself a couple and lay them aside for whenever.

 

[riphip]

Rock auto: Blend door lever (7 position switch) fits 1983 - 1991 $13+


Rick

 

[mankypro]

Well i was just out there troubleshooting. Seems like the door move back and forth but sticks at the top, almost like it doesn't want to close completely at the top. I tried jiggering it a bit to see if there was some debris up there but my hands are too big to fit. At this point there must be something wrong with the door.

Anyone know if in defrost the door seals towards the firewall?

 

[riphip]

Defrost seals up and down on the driver's side vacuum actuator, to the left and above the panel blend door.

Rick

 

[mankypro]

tearing off the dash and the airbox is not something I feel like doing. I wonder what it would cost to have the stealership do it...