455man

Anyone know how to remove the heater fan switch on a 72 Cutlass with A/C? Its hard to see from under the dash but I was assuming there is something holding it in from the back side. I've narrowed down my heater problems to the switch. I can get the fan to work on all speeds but low med while jumping power around the switch. I have power going to the switch but none coming out. I was going to remove it and clean it and if that still does not work, replace it.

oddball

Two bolts, one on the bottom, one on the top. Hex heads, something like 5/32? I can verify tonight. Comes out the back, so you have to get the **** off. Should be an allen set screw going in the side of the ****.
I've seen several that were burned. I'd strongly recommend getting a new one. Also, pull the switch out with the harness attached so you can work it apart where you can see it. I've broken several of the connectors. The switch tends to get hot, the connector gets brittle, it's all downhill from there.

455man

Great thanks. I might need to remove the lower vents to be able to see the bolts. Or maybe use a mirror. I seen the allen screw and will remove it.

Allan R

Look on page 12 - 172 of this link: http://wildaboutcarsonline.com/membe...al_Sect_12.pdf

To rotate the image when it's open, press Shift,Ctrl and the + key at the same time

MDchanic

I've disassembled, cleaned, and fixed a couple of them.

It's worth a try before you spend money. Worse comes to worst, it's still broken when you're done. Just remember to keep track of EXACTLY which direction each piece fots in, as it's easy to reverse things.

- Eric

Lady72nRob71

The A/C vent manifold will probably need to come off, as well as the lower dash valiance for room to work. Check the contacts in the connector for burns. If discolored, remove each and clean or replace as needed.

455man

Thanks Allan. I was wondering where the resistor was. I was looking at a different manual on the the same site that did not show the location.

MDchanic I figured I try cleaning it first also.

MDchanic

The resistor is poking into the fiberglass evaporator housing on the engine side of the firewall. Rob has some great pictures of it.

- Eric

oddball

Agreed, I'm just paranoid about electrical fires in 40+ year old cars.

455man

The bolts are 1/4. Took apart the switch, cleaned it and only got one speed to work. So I'm going to buy a new switch.

Allan R

sounds about 'par' for the course. I don't think you can get those from your local auto parts store though. Fusicks has them on pg 12 of their catalogue
395168 Air Conditioner Fan Speed Switch 1970-72 all with A/C 29.50

455man

Thanks. That's the one i ordered. Other sites were slightly more expensive.

455man

Sure enough right after I ordered the switch I started looking at the wiring from the link Alan posted and noticed that my wiring was not right. I dug around and found a hidden wire, plugged it in and the fan works on all speeds. Only problem is the speed right above low does not increase it stays on low. The top two work fine. So i have a three speed. Any ideas on that? Switch or resister?

Now I'm moving onto the duct work. I'm missing some pieces and some are broken. Is there a diagram that shows the ducts on an A/C car? And where do I get the duct work? Make a parts needed thread?

Allan R

So that would be 'med' speed? The switch has 4 poles off/lo/med/hi. If you're only getting off/lo/hi? It's the switch. I had the same problem with mine. if you leave it long enough all you will have is hi.(well at least that's how mine crapped out).

Hi ho Siilllllllver! Remember that website I suggested?? WAC? FREE membership??? Great resources??
Take a look: http://wildaboutcarsonline.com/membe...ct_1_-_1.2.pdf
http://wildaboutcarsonline.com/membe..._1.3_-_1.5.pdf
If you take a look through both of these links you will find a lot of info on the AC and duct routing. Scroll through all; it's not all sequential..

Where can you get the parts? Check with John (2blu442) Eric (jensenracing77) or Scott (Oldspackrat). They part out these cars regularly and the parts from 70-72 are interchangeable.

Lady72nRob71

Do make a parts wanted thread of the parts you need. Lots of these A/C parts are available used.
The speed issue you have is a bit baffeling...

Allan R

I thought so too. When my fan switch started malfunctioning it was on the lo setting. Then it worked its way up to the med setting; so the only functional position was hi. It could be the resistor, but more likely it's the switch. Have a look at the schematic 72 CSM on page 1-13 http://wildaboutcarsonline.com/membe..._Section_1.pdf

455man

Thanks for the links. I'll check them out. I am on WAC. I've been looking through some of the manuals but have not found the a/c ducts yet. I'll check out the links you posted.
With the switch I have low, two mediums and hi. The off switch is with the heat/def/vent/AC settings. So the low and low medium stays the same speed. I thought it was odd but happy I have a fan working.
I've bought from Scott before I'll hit him up.

455man

So I got the switch working but my heater fuse blew. I put a new fuse in it but now I wonder what's making it hot? Too much resistance in the fan, wiring, bad connections? Any common problems in these old cars? I'll run it some more and see if the new fuse blows.

Allan R

2 things.
Are you saying the fan switch is getting hot, or are you saying the fuse got hot and blew? Is this causing the fuse box to overheat? Not quite sure what you were saying so I'm fishing here.....
If the fuse just blew, it could very well be from age. If you're getting heat build up on the fuse panel, you might want to check the resistor in the fan speed circuit.

455man

The fuse just blew. I thought maybe it was old. It was in the car when I got it. This car had been sitting about 5 years before i got it. I'm just worried about putting everything back in the dash and having more fuses blow. I have not drove it since putting the new fuse in due to a week of rain but I'll get it out this weekend. I was just assuming something was getting hot.

Allan R

From the sounds of it, you're ok. Just to be on the safe side, on a car that old I'd replace all the fuses anyway. Give you a chance to see if there's any corrosion building up on the ends or on the fuse block holders. That can also cause the fuse to blow when there's an arc from bad contacts.

455man

Cool. Thanks for the assurance.

455man

So I'm putting the ducts back in...slowly. I noticed that when it's on the Defroster setting that air comes out the floor and defroster. Is this normal on these old cars or is there a vacuum leak?

MDchanic

The system is designed so that a small amount of air will come out the heat duct on Defrost, and a small amount will come out the defrost ducts on Heat.

If the amount feels equal to both, then there is a problem.

- Eric

455man

Ok. Thanks. I'll check that out. So I should notice a difference in the amount of air coming out of the defrost when I switch it to heat.

MDchanic

With the fan on High, you should just be able to feel a little air from the outlet that's not turned on.

- Eric