My 97 Dakota a/c will blow cold with no issue's first start of the day and quit blowing cold after bout 5 mins. the compressor kicks off, also if its the first start and I let it cool down and then shut the truck off the compressor wont kick in either. I have replace the switch on the pump and the switch on the can and the ambient air temp switch with no luck. I put a test light on the pump and it lights up when its on with the switch ( I tested the wire that is next to the clutch). The low side is carrying 55 psi on the freon but I don't know about the high side any suggestions?

 

55 psi, on the low pressure side? Is that with the compressor running? If so, that's VERY high.

If you mean 55 psi "static" that doesn't really help. It doesn't give any indication of the compressors performance. Systems are charged by weight, not pressure.

Get a gauge set. Without both the high and low pressures you can't properly diagnose the a/c system. Don't just bleed it out or add refrigerant either.

 

55psi on the low side I will see if autozone has a rental on a gauge set.

 

Ok new update took it to the shop a/c was over charged the mech said was he clutch, they tapped on it and it started working so I changed out the clutch with a spare compressor that I had and it does the same thing. Now that the system is serviced correctly I know the pressures are good any suggestions before I start throwing parts at it?

 

Did you only replace the front disk/clutch plate?

If so the magnet is bad you need to replace all the clutch assembly usually you do its a kit magnet pulley and new clutch plate all in one.

you don't just replace the front plate.

 

With a test light or Multi-meter reading volts, recreate the conditions with the light in place like when you were testing.
Is it always 5 minutes like you stated or does the time vary.
Could there be a broken wire somewhere that is what the light is for.
If there is a wire broken and then the light will go out.
Could be a relay getting hot.
Does taping on compressor make it start back up?

Just some things to check

 

yes I replaced the whole clutch coil and everything

 

I will try the test light today on the wires

 

When you replaced the clutch coil, what did you set your air gap to?

If too high, it won't engage properly.

(No, I don't know the number for a 1993 compressor ... my manual is for a 1988.)

RwP

 

I don't know what an air gap is or that there is an adjustment for now my curiosity is up.