Q #2 73 A/C Problem

[CAPNZ]

My second question is.....

My Frigidaire A/C compressor won't engage. The clutch does'nt engage when I set the selector to Max or A/C Norm. Now, there are 2 wires coming from the unit. A green and a black. The black goes to the ground screw on the unit and the green goes up to the wire harness and is met with another green wire and black wire and they are terminated to a 3 terminal spade type connector. Looks original. There is no fuse or relay that's plugged into it? To me it seems the circut is open without something plugged in there. ?????? Any suggestions.



TIA

"Jeff"

 

[Bill75]

It could be that you're low on Freon and the low pressure switch is preventing the compressor from engaging. One simple way to check is to follow the wires back from the compressor a short distance, you should see a round plug/socket, on my 75 it's mounted close to the fender. Unplug the two wires from the compressor they should be male pins. Insert a temporary jumper across the two female pins in the socket, this will bypass the low pressure switch and allow the compressor to start. If it does, it's most likely low on Freon, if it doesn't it may be the compressor. DON'T run the compressor very long with the jumper, without refrigerant it may not be getting oil it needs for lubrication.

 

[magoo]

That 3 term connector is for a special fuse link. Without it the compressor will not run. I think I still have some at home if you can't find one. It should be avail and not expensive. If the compressor still does not run it is probably low on freon as Bill said. If so, only jumper it long enough to charge it properly as he said. Do not jump it to drive. Hope it helps.

Mike

 

[CAPNZ]

Thanks Mike, I think that could be it. You think I can get one from GM?

Also, I spoke with a guy at a A/C shop and he thought it went to the dryer unit and connected to a 3 prong sensor. HMMMMM? Now I failed to say that the 3 wire female spade type connector has a metal clip on it that would snap on to a round pipe to keep it in place. Although, the wires won't reach the pipe on the dryer unit. I'll try and find the fusible link. Any suggestions will help. ALSO I took my TVOM and measured 12+ vdc across the two green wires on the open connector. And from the black wire to each green I got 0 volts.

"JEFF"

 

[CAPNZ]

Thanks Bill, the two wires coming off the compressor is a female plug and they go to that 3 prong connector. One green from the compressor one green from the wire harness and one black from the wire harness.
?
"JEFF"

 

[magoo]

That connector with the metal clip is definately for the special fuse. I believe that they used to clip somewhere very near the compressor. I checked at my local NAPA store yesterday and they still have the fuse. They said it was about $3.00. If you can't find one let me know. Good luck.

Mike

 

[Bill75]

Thanks Bill, the two wires coming off the compressor is a female plug and they go to that 3 prong connector. One green from the compressor one green from the wire harness and one black from the wire harness.
?
"JEFF"

A view from the top with the connector unplugged and a view from the side showing the location of my low pressure switch.

 

[Ludigdrums]

If you are getting the proper voltages and such you might also want to check the air gap between the clutch and the compressor. If there is too big a gap, it will not engage even if you have the correct voltages/freon/etc.

The air gap is real tiny, like .02 - .04. It looks like they are practically touching.

I found this out cause on my '87 Monte Carlo, the A/C stopped working and everything else checked out OK. The compressor would engage only if I tapped it (of course with the A/C controls on). My air gap was almost 1/4". Tighten it up, and all is well!

This is probably not your problem, but hey, you never know!

Good luck!

- Jeremy

 

[CAPNZ]

THANKS GUY!
"Jeff"

 

[CAPNZ]

Thanks Mike, I'll call them.

"Jeff"

 

[CAPNZ]

Mike, I called the NAPA guy here and he had no clue what I was talking about.
You got a part# ?
Also, Bill uploaded two pictures. The fist one is similar to mine. I have the dryer unit
with the cap on it but I don't have the other part were it looks like it plugs on his car.
TIA
"Jeff"

 

[magoo]

Hi Jeff,
The NAPA designation is "fuse", and the part no is 208820. The line code which you shouldn't need is TEM. The local store has 9 in stock.
The 2 prong plug in Bill's post is the low pressure switch as he said. You may not have it. If you do it is the 2 wires coming to it that you would jump to make the compressor run until you got enough charge in it to raise the pressure. If your compressor runs after you put this fuse in the other posts won't really matter. I would suggest that you have the system checked for freon anyway so you don't blow the fuse again. If your system has a "sight glass" you can run the a/c at a fast idle, (1500-2000 rpm) and if you don't see bubbles passing in the sight glass the system is full. Also, that round clip on the plug where the fuse plugs into is to clip to the rubber a/c hose right near the compressor. Let me know how you make out.

Mike

 

[CAPNZ]

You DA MAN!
Thanks Mike. I'll buy 2 and after a check to see what happens I'll take it in.

"Jeff"

 

[CAPNZ]

I bought two Mike.
Plugged it in and nothing!
So I'll take it in. Also the fuse/link has SBC printed above the terminals. You know what that stands for?

TIA
"Jeff"

 

[CAPNZ]

Whoops!
Almost forgot Mike. Now my highspeed A/C blower doesn't work.
When I got the car the in-line 30amp fuse was blown so I replaced it and it worked fine. Now after taking out the A/C Heater control to put the string back on the pulleys
it stopped working.
HMM?
I double checked and all the wires are seated in the control. I'm wondering if when I tried the A/C with the new fuse from NAPA I blow something else out?
TIA
"Jeff"

 

[CAPNZ]

Anyone have a part# for the highspeed blower relay. It's the one on the heater box.
TIA
"Jeff"

 

[CAPNZ]

OK, I have an update. I read the archives pertaining to Hi-Fan A/C and a lot of the people say to check the relay for high speed fan. So, I just got done taking it out, (the one on the blower box) and bench tested it. It worked fine. so I hooked it back up, (with the cover off), and tried the HI fan with with the A/C control set to MAX A/C and nothing. So while the car was not running I took a toothpick and tripped the contacts on the relay and the high speed blower kicked in. It seems there's always 12vdc going to the relay. Although it's not being energized to close the contacts.
Now, there's another relay on the left fender by the washer bottle. It has a post on it with the two orange wires and 2 in 1 plugged in wire conector. Could this be bad?
The 30amp in-line fuse is fine. I want to get this working again BEFORE I take it in for the A/C.
TIA
"Jeff"

 

[OH6A]

You will be very happy if you replace the whole a/c system with one made by Hot Rod Air. See HotRodAir.com. It will even hook up to your 73 switch. From inside the car, you cannot tell that it is an aftermarket unit except it is always cold, it uses 134a and it is guaranteed.

 

[magoo]

Jeff
I don't think the relay you're looking at is bad. I think what you're calling a relay is a resistor that controls all fan speeds but high. I don't believe it has anything to do with high speed. Check for power on both sides of that in line fuse and make sure it is connected. That is what controls high speed fan. I've been busy at home and work but I'll try to check all your posts tonight and see where you're at.
Mike

 

[CAPNZ]

Thanks Mike!
I just went out and checked the voltage of the in-line fuse with my DVM. It jumped back and forth from mV to Volts. I could'nt make out the volts because it went to fast.
Almost like a capacitor was charging & discharging. I'll check back tonight.

"Jeff"