Ok I have the A/C working very well in my SA, vent temps in the 40's vs the vent temps of 65 in my DD this was done in the afternoon at about 105 degrees. Classic R12 vs R134A.

But here is where I am stumped, I have already changed my blower motor as it blew the fuse when ever I put it on (for heat). But the flow from the dash vents is weak can barely tell it's on. My goal is to be comfortable and have to turn it down because I am getting cold lol.

Has anyone experienced this?

Has anyone been able to improve the flow?

thanks

 

Mine flows quite a bit of air, even on the low fan speed setting. If you haven't already then I would check to make sure the flaps on the heater box are working correctly and it isn't just blocking them all off or something. Even with my cobbled together A/C system running R134a I only need the low speed setting to be fine.

 

possible the blower motor is weak? they ARE really old. even good ones don't move as much air as like a modern car. the FC book has a chapter on how the big the blower motor is.

oh and also there are seams between the blower and evaporator, and the evaporator and the heater box, these are sealed with foam, and if the foam is gone the air won't make it out of the dash

 

Ok so it's not a weak setup but there may be an underlying issue. I can easly feel on my hand if I put in front of the vent but aimed at me face not really feeling anything. The vents did not work at all but perhaps it's still not right

appreciate the input

 

The blower motor was changed with a brand new one about 2 years ago and 3k miles, I suspect at the seam may be an issue, I'll take a look at that as well. Perhaps, my F350 moves some serious air so didn't know if it was a matter perception. But I do know the foam was marginal at best

Will check it out as well

 

Well I'll be after gettign might not so young not so slim butt under the dash there was air escaping and blowing towards the firewall .... fixed still seems kind of week thou ......

 

There is a jumper wire that needs to be installed on the resister mounted on the fan whenever a/c is added. It is designed so to speed up the fan to compensate for the added "back pressure" of the a/c evaperator coil. You need to check to see if your resister has the jumper, if not adding one will boost the speed and provide more air at the vents.

 

wow awesome tip there .... do you by chance have an image of said jumper?

electrical is my least favorite thing even on these super simple cars

thanks

 

I do not have a picture of the jumper but here is a pic of the resister.



It is located on the back of the fan housing where the wiring harness plugs into the fan housing. The jumper would plug into the two lugs that are hidden in this pic by the foam plug. Just make a jumperout of fairly large wire and two female spade connectors and plug it in. You will probably have to remove the fan housing to get to the resister, but its not that hard to get it out.

 

^Always wondered what that was! lol Guess I learned something today.

 

So how does this work for the 85 cars? It looks like a jumper in this position will do nothing. Those two connections, C1 and C are connected via a resistor, while C is tied directly to H1. I also have a connector from C1 to the motor. From the wiring diagrams, it would seem that in an AC car, the H from the blower control is sent directly to the motor, bypassing the C1/C resistor. If you removed the wire from C1 in the plug and moved it to C, you would bypass the C1/C resistor.
For note: on the resistor pack, terminals are L,M,H1,H2 and C1,C. On the wiring diagram they use L, M1, M2, H. I assume that L=L, M=M1, H2=M2, H1=H, based on the wiring of the resistor.

 

I cannot find a diagram that shows the connectors that you refer too but when I look at the 85 wiring diagram it shows the jumper I mentioned. It appears to me that there is a small resister that is in the circuit between the resister set and the motor that is bypassed by the jumper. There are three additional resisters that slow the motor for the lower settings but the fourth is in the circuit in all settings, unless it is jumped. When I put my jumper in it did increase the speed of my blower.

 

But the previous post is valid for an early (4/78) SA?

 

I going to say yes. In fact mine is an early SA and it has the place for the jumper so I assume that they all have it. That having been said the 79 wiring diagram does not show it. If yours does not have a resister set that has a place for it you can replace the resister set with one from Black Dragon, which I know will have it. They are interchangeable.

 

From looking at the guts from a late model unit, there is a Green wire coming from the 2 pin connector to the motor. I think this is the motor drive wire. Currently, on a non AC car, this wire goes to the C1 terminal, thus passing through the resistor. If one was to switch the wire to the C terminal in the same connector, the additional resistor would be bypassed. Does your jumper retain the wire in C1, while connecting C1 to C? In this configuration, the motor speed would increase as the resistor would be bypassed.

The way this resistor bank works is:
Terminal L = current must pass through 4 resistors to C1
Terminal M = current must pass through 3 resistors to C1
Terminal H2 = current must pass through 2 resistors to C1
Terminal H1 = current must pass through 1 resistor to C1
Terminal C = current must pass through 1 resistor to C1

If one was to connect the motor to C instead of C1:
Terminal L = current must pass through 3 resistors to C
Terminal M = current must pass through 2 resistors to C
Terminal H2 = current must pass through 1 resistor to C
Terminal H1 = current must pass through 0 resistors to C

I don't know how this would function with just the 4 pin connector. Where would the motor lead come from? How would the extra resistor come into play? Just jumpering the two C terminals together would do nothing.

EDIT:

It would seem that according to the wiring diagrams, the 79's may not have a jumper as they don't have AC listed. 81-83 have a jumper that can be added and 84-85 require the position of the wire in the connector to be changed.

 

hmm after taking it all apart apparently there are two blank spots on mine

 

Got a pic?

 

Mine? Didn't think of taking a pic, I had to put the car back together as we have our local club meet tonight and the the "monthly rotory meet" with the 8's Friday night

It was molded but did not have the male connectors there to jump errrr

 

Here's what my 84's with AC have. Resistor is on the rear of the blower motor box. The green line shows where the jumper was. 3" Green wire with plugs on each end. Not in the picture because it is heading for Victoria, BC tomorrow.

 

super awesome thanks for the pictures!!

yup only thing is mine did not have the male spade terminals

I turned the fan on while I had it down crap if the air from the vents felt the same way I'd be super happy, but it doesn't ;(