a/c compressor not comming on

[nawlins-tim]

I recently got this new motor set-up and running fine. Bought some new hoses . I had the vacuum hose to the heater valve mixed nup with the other one that works the vents in the dash , so the motor was killing when I turned on the a/c. Now that - that is fixed the compressor wont come on. Fuse is o.k. The fan comes on bu tnot the a/c compressor . What should I check next?could it be that relay or is there one at all. I don't know where to go with this.
Any ideas???????

 

[dedub]

There should be a green wire that goes to the compressor. Is it hooked up? Is the compressor grounded well with the black wire? You might want to put a multi meter on the green wire while it's disconnected and turn the A/C on. It should read 14v while the motor is running. If no voltage start tracing.

 

[nawlins-tim]

There should be a green wire that goes to the compressor. Is it hooked up? Is the compressor grounded well with the black wire? You might want to put a multi meter on the green wire while it's disconnected and turn the A/C on. It should read 14v while the motor is running. If no voltage start tracing.

"That sounds wise"= on my compressor the plug has a green and I think a white or brown maybe. do you know anthing about that relay next to the hvac fan. I found one for sale on a g-body site that calls it a HEATER CONTROL RELAY. And would you know where that blower resistor is. I eventually want to have gone through the whole system and have it all just about in tip top condition. Thanks alot my co-80 ss partner

 

[dedub]

I can be of some help but not much on this. I don't know much about the relay, I'll have to look in my Chelton and Haynes for you. I do know the resistor is directly under the heater fan cover. Right where you "plug in" the connector there are a few small self threading screws. The wire colors are yellow, light blue, orange and one other. underneath that connector is the resistor which looks nothing more than a coil or a curly piece of wire.
You said your fan was spinning OK though so I'm not sure you have to go that route. I have to run to look at a friends Vega but I'll follow up on this post tonight once I look at my books.

 

[megaladon6]

has to be asked, are you sure the system is charged? if there's not sufficient pressure the compressor won't activate. there's also a pressure sensor (i think it's on the reciever/dryer) if this is faulty it deactivates the system.

 

[dedub]

Here is a helpful diagram
http://www.maliburacing.com/wiring_diag ... tioner.jpg
This should be pretty close to what you have. As you can see the blower motor, resistors and relay are on a different circuit than the A/C compressor and the pressure cycling switch that megaladon mentioned. Focus on that green wire that comes from the switch, make sure the compressor is grounded and the system is charged. If you still can't find the problem, you can always temporarily bypass everything and hotwire the compressor with a temp. switch. That would be just to bump the switch to see if the compressor will kick on. This is not intended to "fix" your problem, just isolate it; do not use this switch as a permanent bypass. Let us know when you have it more isolated.
good luck

 

[nawlins-tim]

Thanks for the help guys. Didn't think of the preasure switch. It was coming on but since I had my vacuum lines that operate the heater valve going to the carb, The car would kill. now that I realized I actually could do without either the car ran fine once with the a/c on. then messed with it later and noticed the comp.quit coming on. well I'll start back tracking once the weather gets better. Even in New Orleans It has been wayyy cold.