| Re: [GMCnet] HVAC Doors [message #362576] |
Sun, 28 February 2021 16:38  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Greg,
Another thought: You may find this chart, a color coded version of the
original in the service manual, useful. Since I completely replaced my
HVAC system years ago, I don't remember the operation of the original.
But, from this chart, it appears to me that your belief that the default
position is DEFROST may be incorrect:
bit.ly/3aZNZq7
or
http://www.gmcmhphotos.com/photos/type-ii-dash-air-condition-modification/p19227.html
Ken H.
On Sun, Feb 28, 2021 at 5:31 PM Ken Henderson
wrote:
> Greg,
>
> The doors undoubtedly need new seals, and the evaporator probably needs
> cleaning, so removing the front as you suggest is a good idea. But, you'll
> gain access only to the doors themselves -- not the actuators. Those are,
> unfortunately, quite well hidden behind the dash. You CAN get to them, but
> not as easily as you're hoping -- so what else is new? :-)
>
> Ken H.
>
>
> On Sun, Feb 28, 2021 at 4:58 PM Greg Crawford via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> If I remove the radiator overflow tank and the windshield washer fluid
>> tank, can I take the front off the HVAC box and access the flapper doors?
>>
>> None of mine work, probably due to the vacuum leak at the control, and it
>> blows out the dash vents in Heat, Vent, and AC positions.
>>
>> I've read that the system defaults to defrost, but mine does not, so it
>> makes me think the door is stuck.
>>
>> If I can get the doors to work, I'm thinking about trashing the original
>> HVAC controls and doing this:
>>
>>
>> https://sites.google.com/site/darbyselky/home/electronic-hvac-controls?authuser=0
>>
>>
>> --
>> Greg Crawford
>> KM4ZCR
>> Knoxville, TN
>>
>> "Ruby Sue"
>> 1977 Royale
>> Rear Bath
>> 403 Engine
>> American Eagle Wheels
>> Early Version Alex Sirum Quad bags
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] HVAC Doors [message #362577 is a reply to message #362576] |
Sun, 28 February 2021 17:35  |
Greg C.
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma: 0
|
Senior Member |
|
|
Ken:
Thank you for the response. I had taken the blower motor out and then the fiberglass housing and plastic extension that holds the blower and directs the air into the AC evaporator. There was quite a pile of Texas acorn caps and sticks in there, along with some hair. A lot of this was stuck in the evaporator fins. I hope to be able to spray some coil cleaner from the front into the fins and clean out whatever may be left in there.
I can see one vacuum actuator from the glove box. I can see the top one by looking up under the hood and peering into the fresh air intake. Do you know if its possible to get to the one on the drivers side of the HVAC box without removing the dash? I'd like to connect my Mity Vac to each one and confirm operation before working on or replacing the dash control head. I definitely want to replace the foam gasketing on the doors.
I've looked at your photos of the removal and installation of your custom system several times. I'm not averse to tearing out the whole dash and building a new one from scratch as you have done, I just don't want to do it this year if I can avoid it.
I didn't arrive at the defrost default idea on my own, I just read it somewhere on the forum.
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
