re: vac control motor that runs def/floor select

[papadiesel]

Hey guys,
Many posts on this issue, usually the firewall vac motor for ac/ heat control. I need to know what the vac control motor is just up behind the control head ( inside firewall ) and if that is the one controlling floor defrost. 1989 Ford f250 7.3with factory AC. Vac is good throughout from the new coffee can to vac sector valve on head control. Mine is the two slider unit with cable actuating heat, cold. When I replaced the vac switch behind the head, I ran the system and saw movement on that vac motor, but it does not switch very well. It has two vac ports on it. Is this the culprit, should it move relatively quickly as all my other vac motors do? I am fairly familiar with these vac systems, but this has me stumped. The AC side works perfect moving to vents on demand and very cold. There is movement to defrost, mix and floor but it is not definite as it was before and blows poorly as a result. Thanks again! PS Cruise works perfect as well, the issue is only with the def/mix/floor motion! Also, moving from cool to heat works perfect as well.

 

[papadiesel]

update: All functions of heat and AC work correctly EXCEPT def/mix/ floor on lower slider. I assume it is controlled by the upper vac motor. If so, can you replace it without pulling the whole heater AC box assembly? thanks again! In this picture top left!

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[papadiesel]

and no, it is not out of my truck or easy peasy

 

[riphip]

You may have a worn out blend door with hinge broken. No fuhn at all to repair, especially in-the-truck.
May have a bad selector switch & get another at Pick n Pull. Pull whole switch out of dash

The vac motor can be replaced in the truck (if you are a midget or removing the front seat). Can be done.

 

[papadiesel]

thanks, vac motor working fine, already replaced selector switch, can you get to the door after pulling the heater core cover? thanks for your reply.

 

[riphip]

Been a long while for mine, I removed the dash I think. I can get the part# tomorrow since I got one each for my other trucks at the time because of 'my luck'.

 

[papadiesel]

thanks!

 

[riphip]

I see some on eBay you can check out (used is not for me on this item).
Tasca Ford has them NEW: E0TZ-18A361-A
$82+
I have 2 but will have to save one for my present driver that I bought years ago for $50 (3x) at Dobbs Ford here in Memphis on my brother's Fleet Account.
If you might have a DEPSTECH WIFI borescope, it would help you greatly BEFORE you buy a replacement. Check Amazon for that.
You may just have a pen or something that has fallen down the defrost vent & is blocking movement of the door.

 

[papadiesel]

thanks man, I do have a scope and when I replace the 34 year old heater core, I will look, thanks again. Mine is an 89, so I think the doors might be a bit different. I have searched like crazy for the 89-91 blend door and cannot find one or even a pic, if 86 is the same I stand gladly corrected. Thanks for your help