| Author |
Message |
Henryk (Henryk)
Junior Member
Username: Henryk
Post Number: 189
Registered: 8-2001
| | Posted on Wednesday, August 21, 2002 - 9:24 pm: | |
Matthew: Check the ohm reading across the LOW pressure switch, next to the drier. If it is zero, than this switch is preventing your compressor from getting power. If so, the system is either empty, very low, or the switch is bad. In a good system you should get an ohm reading, even if small. The switch requires at least 2 Bars of pressure to allow it to give power to the compressor. I just went through this in my car. |
Dr Tommy Cosgrove (Vwalfa4re)
Junior Member
Username: Vwalfa4re
Post Number: 235
Registered: 5-2001
| | Posted on Wednesday, August 21, 2002 - 8:55 pm: | |
Hey, Matthew, that's a cool find. Could you post the paper so we can all see it too? |
Lawrence Coppari (Lawrence)
Junior Member
Username: Lawrence
Post Number: 195
Registered: 4-2002
| | Posted on Wednesday, August 21, 2002 - 4:43 pm: | |
If you have a short, a fuse will blow or your will melt a wire. Rather than a short, you probably have an open circuit.
Check the resistance across the leads to the compressor clutch. It should be about 3-5 ohms. Did you check to see if you have voltage at the clutch leads - the other side of the break where you would check resistance? |
Robert W. Garven Jr. (Robertgarven)
Junior Member
Username: Robertgarven
Post Number: 73
Registered: 2-2002
| | Posted on Wednesday, August 21, 2002 - 2:13 pm: | |
The early cars leaked R12 bnormally and the OM says to refill yearly. If you have not used or refilled the system in a few years it is probably empty. i filled mine up and it worked great. If you get a chance take a course on auto AC/heating at a local college, very informative. |
Matthew Lemus (Mlemus)
New member
Username: Mlemus
Post Number: 7
Registered: 8-2002
| | Posted on Wednesday, August 21, 2002 - 2:07 pm: | |
I have freon. The compressor does not have power. Could it be a short somewhere? While under the cover I found a piece of paper dated June 12, 1978 that have the daily status of 20 cars in production. Chassis numbers 24806 to 24826. mine is 24825. From what I can read of it. Number 24812 had a bad right rear shock from the start and 21810 misfired on every start up. |
Matthew Lemus (Mlemus)
New member
Username: Mlemus
Post Number: 6
Registered: 8-2002
| | Posted on Wednesday, August 21, 2002 - 1:36 pm: | |
Thank you so much. I will give it a try. |
Steve (Steve)
Junior Member
Username: Steve
Post Number: 195
Registered: 2-2001
| | Posted on Wednesday, August 21, 2002 - 12:57 pm: | |
Matt lift up the front bonnet and remove the vinyl spare tire cover from the car. Look at the receiver/dryer (black can) on the passenger side up in the corner. You will see a switsh mounted in a cross fitting. Unplug it and short out the wire with a jumper. With the ign. key on turn on the AC fan switch and listen to see if you hear the AC compressor clutch kick in (CLICK). If thats OK then start the car and with the jumper still in place look at the sight glass in the top of the receiver/dryer. If you see some bubbles or no bubbles then the AC is out of freon.Time to check for leaks. Good luck |
Matthew Lemus (Mlemus)
New member
Username: Mlemus
Post Number: 5
Registered: 8-2002
| | Posted on Wednesday, August 21, 2002 - 12:36 pm: | |
I am not sure if there is refrigerant in there. The compressor seems to be powerless. The fan does come on and the water pump is warm. I do have the schematic. Should I put a volt meter on the +12v line? |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 961
Registered: 1-2001
| | Posted on Wednesday, August 21, 2002 - 9:41 am: | |
Matthew -- There are max and min refrigerant pressure switches in series with the AC clutch winding (near the dryer I think) -- are you sure that you have refrigerant in the system? If you can find the max/min pressure switches, one of the wires should go to +12V when you turn on the AC system (this can at least confirm the upstream +12V power stuff is OK -- although, if the right hand radiator fan is coming on when you turn on the AC and the water temp is warm, this is another indication that it is OK). Do you have a OM with schematic? |
Matthew Lemus (Mlemus)
New member
Username: Mlemus
Post Number: 4
Registered: 8-2002
| | Posted on Wednesday, August 21, 2002 - 8:48 am: | |
My 78's air does not work. The blower in the cabin, the fan in the front and the fuses all are in order. But there does not seem to be any power to the a/c compressor. Any Suggestions? |