I recently inherited my brother in laws 1997 Dodge 1500 and the AC has seemed to stop working. I drove it home from his house to mine that is a 3 hour drive and it worked great. Now that is has gotten hotter outside it seems to have quit on me and I am clueless as to where to start. I know it has plenty of R-134 in it; I actually think it had too much I put my gauge on the low side and it was in the (100 psi) warning zone so I let some out down to about 32 psi and it worked for a little bit and I put the gauge on it again and it is shows in the red again. I know there has been some work done on it a year ago because the motor was replaced with a new fresh 360 but I cannot ask my brother in law because of his recent death. When I say is not working I mean the there is not cold air and the compressor is not turning on. The odometer reads 197000 so I know things have been used a lot. I just want to know where to start or what should I replace first?

 

Let everything cool, overnight would be good, and check your pressure again in the morning, sounds like there is a blockage in the system though......

 

HeyYou,
Checked the pressure and it is better back down to normal AC ran a little bit this morning and now it is not working again. Any suggestions as to where a blockage maybe? I can handle the repairs but I just don't want to replace everything if I don't have to.

 

check to see if the compressor clutch is engaging...if it isn;t then tap the center of the clutch (carefully with like a wooden hammer) if it engages then you have a clutch gap problem. If it never engages...then you can bypass the low pressure switch on the accumulator by shorting out the connector with a paper clip (turn the engine off first and then put your paper clip in and start the motor. If the compressor engages then, you have a freon level issue..

 

as said, check that the compressor is running, as you can only accurately check pressures with it running. when compressor is not running, then low side pressure will falsely read very high.

also be aware that pressure is related to temperature, so you can overcharge it and read normal pressure when everything is cool, and have it way overcharged and overpressured when everything is nice and hot. don't ask me how i know this...

also, compressor can kick on/off based on signals from low pressure and high pressure limit switches. too low or too high.

 

If it is a blockage, it is probably going to be at the orfice tube. Trouble is, what is it blocked WITH? Most of the time, it is metal shavings.......... generally from a compressor that is slowly eating itself up.

If the compressor runs, watch what the pressure do while it is running.