Desperate Heater Chapter II, The Fuse.

[Chaplain Kent]

I got picked up the switch today. It is a three position switch with a similar wiring harness and a mount that will need some alteration but will work. When I tried the switch I found the fuse was blown. I replaced the fuse and it immediately blew again. Then I realized that the blower was not working with my AC Blower switch, obviously the fuse keeps blowing. Last summer I had trouble with the blower which was almost frozen up. I freed it by using a liberal amount of lubricants and it has worked fine ever since. Now I wonder if I am re-visiting my old blower problems. Any ideas? How can I test the blower without taking it out? This blower will be a bear to remove and I doubt that I would be able to do it myself. If it needs to be replaced where do I get the blower?

[Chaplain Kent]

OK! after all the great replies to my desperate pleas, I figured there was no other choice but to tear out the dash and take out the blower. What a job!
First off to all of you who said in previous posts that it comes out without removing the dash, forget it. At least mine had to have the dash removed. The blower, heater core and AC is one unit. This bear is attached to a plenum which distributes the heat and cold to the cabin and to the defrosters. There is a GM part# and I am on my way to GM to start my search. Pictures below. Now I might as well do something with the old dash because I doubt I will ever get it back together.
The last picture shows the importance of having a good helper on a project like this.

[azflycaster]

Glad to see that Cromwell is supervising the job!

[GlenCoombe]

Wow! That looks deep Kent . I don't know if I'd be able to find all the parts, let alone remember where they came from.
I seem always to ask my parts suppliers to charge me their core charge and then return the old part after I've done the R&R so I can attempt to accomplish it the same day. I hate coming up with leftover parts at the end of a job.
Speaking of jobs....that's what keeps me from doing this kind of work on AS One as it has to be on the road working or at least I do.

[ALANSD]

May be different in my model as the heater core is removed thru the panel in front of the passenger seat, as for the blower thankfully I have not yet had to find that out.

[Chaplain Kent]

Alan,
I too have a heater core behind that panel, this is another heater core with the blower attached. I am attaching a picture of the floor area and the heater core which is down there, is it the same as yours?

[PeterH-350LE]

Hmm,
I wished i would have read this entire thread before..
The unit you removed from your dash has nothing to do with your heater, and the switch has nothing to do with your A/C.
It looks identical to my 79 setup.
What you removed is the the A/C fan and the evaporator, which should all be controlled by a different switch on the dash.
The Heater fan is located in front of the heater core and should be accessible from the front engne compartment.

[Chaplain Kent]

HMMM
Peter,
This fan was ducted into the plenum above which is the defroster and into the heat outlets. Further this fan motor did not operate from its switch and blew the fuse when I turned it on. OK, now where is the heater fan?

[PeterH-350LE]

Originally Posted by Chaplain Kent

HMMM
Peter,
This fan was ducted into the plenum above which is the defroster and into the heat outlets. Further this fan motor did not operate from its switch and blew the fuse when I turned it on. OK, now where is the heater fan?

This is the location of the heater fan motor on my 79

[Chaplain Kent]

That was easy, took about five minutes to get the motor out. I will be philosophical about this. The motor I took out was going bad and would soon need to be replaced if not now soon. The ducting was crazy as I said the defrosters were ducted to my AC!. All the heater duct hose needed to be replaced. I will be able to beef up the sound insulation against the firewall. I will have a nice new looking dash board if I can figure out how to replace what I took apart.
I imagine that the AC will need to be charged after it is put back together. When I took the lines apart there was no sound of gas escaping.

[3Ms75Argosy]

Chaplin - I believe most defrosters go through the A/c to help dehumidfy the air prior to hitting the cold windscreen. This helps draw the moisture off the window and into the air, letting one see faster.
Take care!
Marc

[Chaplain Kent]

Well the plot thickens. First, thanks for the reply Marc but in our system the AC and heater are separate. Someone at sometime duct- taped an AC vent hose into a hole they cut in the defroster plenum. It was quite a sloppy job and I am ashamed I did not notice it before.
OK, I tested the heater blower and it is fine. I also tested the blower motor for the AC and it works, albeit squeaky as usual. So now I am back to square one, the switch. Obviously the switch I got from Chrysler did not work.
I have ordered a new motor for the AC to rid myself of the squeak and will put back the old heater blower as it seems to work fine. The switch has me stumped. GMC said it appeared to be out of a 78 to 84 pick-up without air so I will make the rounds of the bone yards again. Although the # on the control head did not match anything in their system.
I have attached a picture of the switch below, there are three (3) contacts not two, one was burned and fell off.

[wahoonc]

ChaplainKent,
If the terminal burned off the switch it was for a reason, either the motor was drawing too much current or the switch was underrated for the task or possibly there was some corrosion? Does the motor have any specs on it? Perhaps you have an automotive electric shop in you area that could test it? Maybe when you reinstall the assembly consider routing the current thru a relay to take some load off the switch.

Aaron

[PeterH-350LE]

Originally Posted by Chaplain Kent

....
I have ordered a new motor for the AC to rid myself of the squeak and.......

Take a real close look at the fans (2), which are attached to the motor. You probably will find that the squeak is coming from the fans touching the housing.
If I remember correctly, there are hold down screws to adjust the fans on the motorshaft. You should be able to move them enough to get rid of the squeak.

[Chaplain Kent]

Originally Posted by PeterH-79MH

Take a real close look at the fans (2), which are attached to the motor. You probably will find that the squeak is coming from the fans touching the housing.
If I remember correctly, there are hold down screws to adjust the fans on the motorshaft. You should be able to move them enough to get rid of the squeak.

The motor squeaked without the fans. I did not find any set screws or allen screws which held the fans on, they appeared to be held on by friction only.