ac light on but not engaged

[jeffmsp]

as title states I push the button and it lights up. Does not appear to be activating the compressor as the rpms dont dip like they always used to when its on and off course no cold air. I have very little knowledge of AC systems but I did make sure everything was plugged in the last time I swapped a motor into the car. This is the first time I have tried to use the AC since last summer. All of the lines and hardware look to be in good working order. I was debating just buying a can and trying to refill the system, but not sure if i should bother with that yet or if i should go inspect the electricals first. I have a protege manual i got online but it is missing the section on hvac so I am not sure where to start.

I have a multimeter and plenty of time on my hands this sunday, any ideas on where I should start? or should i just try to refill first even though it appears the compressor is not putting load on the motor?

thanks for any advice

jeff AKA the HVACnewb

 

[dominoy2k1]

have you tried checking the ac fuse?

 

[jeffmsp]

yes i inspected all fuses in footwell and engine bay

 

[jeffmsp]

well its almost sunday so im probably just going to test voltage going to compressor and see if its getting any juice. il let ya know how it turns out.

 

[poundNP5owner]

What did you find? I'm thinking if you need an engine swap, and kinked the lines or somehow released the refrigerant then that is your culprit.

The light will come on for most cars even if the compressor is out. Keep me posted, I'm having my own HVAC gremlins on my wife's P5.

 

[stdntDrvr]

i'm having the same issue in my msp. at first it was the whole 'blinking light' thing...and now the compressor doesn't turn on when the a/c light is on...i was thinking it was either the fuse or the HVAC control unit...i know there were problems with those burning-up in the past. i can't get anyone to give me a suggestion/answer to what the problem is.

 

[Stormtrooper77]

This just happened to me. You guys should check your high pressure hoses for the AC. Mine had tiny pin holes. Got that replaced, got the system recharged and voila.

 

[stdntDrvr]

This just happened to me. You guys should check your high pressure hoses for the AC. Mine had tiny pin holes. Got that replaced, got the system recharged and voila.

...but my compressor isn't turning on...you would think that it woud if the switch is on, right? that's why i thought it would either be the control unit in the dash or the fuse.

 

[poundNP5owner]

most a/c systems will not turn on if it is low on refrigerant.

 

[stdntDrvr]

it was blowing ice cold and then just all of a sudden stopped...i had driven around 10 miles...stopped at a red light...the a/c light was flickering on/off...so i started messing with the plug on the back of the control unit...the light came back on, but the compressor didn't.