Hi guys, iam looking for help on my A/C. Im trying out that freeze 12 freon so i went through and put a new Napa expantion valve, reciever/drier, new ester 100 oil, flushed the evaporator and condenser and then evacuated the system.So now whats happening (with the system all evacuated and charged up) is the engine will idle up properly to compensate for the load of the compressor but the compressor itself wont kick on. However it will kick on if i jump it. My system functioned fine last summer when i was trying the 134a untill it eventually leaked out. However the 134a never really got that cold.

Sooooo. does anybody have and clues to what i might want to check? Thanks in Advance guys!

 

Might need to adjust the A/C amplifier behind the glove box.

 

Might be the clutch for the compressor?

 

Ive tried adjusting the amplifier with no luck and the clutch engages fine because it works fine when i jump it. Im thinking the amplifier migh be faulty so i need to see if there is a way to test it.

 

Are you sure that you put enough freon in the system ?, there is an presure switch that has to see a certain presure before the a/c will function.

 

like "myyota" mentioned. bypass (jumper) the low pressure switch and see if it works that way.

 

I did jump it and the clutch and the compressor do work good. I put two cans of freeze 12, which is almost the perfect amount( maybe a little more if anything) of freon.

 

I'm curious to see how this pans out. I experienced the EXACT symptoms so I gave up, disconnected it all, and threw it in a box during my Frankenyota project.

A friend of mine has an 89 and swears up and down the amplifiers blow a component and thus shutdown the entire system. So if is a bad component it is definetly the amplifier or low pressure switch.

 

I seriously believe it's the amplifier too. Iam gonna try to get another one at the junk yard. It's worth a shot.

 

Sweet, post your results! You might have to be picky about whay years to get the amplifier from. A few things changed down in that location throughout the late 80's and early 90's. Better fan motors, stronger fan resistor packs, etc.

 

Your definitely right on needing to be picky on the amplifiers. I managed to get two amflifiers. One was out of a '86 and the other was out of a '88. The '86 amplifier did the same exact thing my original amplifier did, it kicks the relay over and will idle the motor up, but the compressor won't engage. The '88 amplifier acted like there wasn't even anything plugged in. Soo I guess I will be looking again for a '85 amplifier this weekend.

 

Yup.... looks like I'll be dealing with the same BS.

The amplifier is relatively small: if you're handy with a multimeter you could test every component on the PCB and attempt to replace the blown out one.

I've been told you can bypass the amplifier, however there are consequences. I guess it regulates the duration of time the compressor runs before shutting it down momentarily for a "cool off period". So by bypassing the amplifier, you would have to switch the A/C off every few minutes to let the compressor settle.