Recently had my AC Compressor replaced after it seized up - shop told me the High Pressure switch had been jumped, but they were going to leave it "as is". Asked them why (previous owner) would have done this, and they sort of shrugged and said "to get it to work" XD

My Question is: is the high pressure switch as easy as it looks to swap out? i.e. just disconnect wire, give it a twist, install new switch, reconnect, and away we go? or is there something more complicated here (loss of gas/fluid, introducing air into system, special tools, etc) i need to be concerned with? i have found a lot of videos and info about the low side, but not the High Side. Assuming there is a schraeder valve (or similar) on the other side of this which will maintain pressure and avoid leakage?

2000 cherokee sport. Pics of bypassed switch attached

 

I'm pretty sure the whole line assy has to be changed. Will need refrigerant removed and recharged if thats the case.

 

Yep, it's that easy. It screws right into the port. The Schrader valve will hold the pressure. Just swap it and plug it in.

The old compressor was likely the reason it was jumped. With the new one, it should work fine.

 

I was mistaken, looks like it should be a quick swap of the sensor like Roberto said. No recharge needed.

 

I don't know what the original owner did or was trying to do. On a 2000-2001 the high pressure is a dual switch. Normally a light green/ blue wire is the compressor engage side and is closed until an overpressure occurs and opens/ kills the compressor. The light green and tan wire goes to the fan circuit and is normally open and then closes to turn on the fan when an overpressure occurs. They appeared to jumper both light green wires with the wire strip...reason unknown. I cant see what else they butchered. That connector should not fit into the switch body with that wire installed. I have no ac on my 2001 so i have green and tan jumpered to turn on fan when i select any ac mode

 

By the way all above are correct about removal. There is a schrader valve in the mounting stem of the pipe so if replacing..let pressure equalize overnight and unspin switch QUICKLY to minimize freon loss. 9/16 wrench fits the nut. I just checked the pipe assy i had hanging on a hook in the garage.

 

Curious - if i yank that wire bridge out - is there a way to know if that sensor still works? it seems cheap enough to just replace if it's as easy as it looks - but - not knowing why the heck they did it in the first place didn't want to start monkeying around with it (i've now owned the jeep for 5 years, never really had any issues, although did get the AC recharged once a year or two ago - so there may be unseen issues/slow leak that i'm not properly identifying)

 

The high pressure is just for the opposite protection of leaks...thats the job of low pressure switch. If your compressor is properly serviced with the correct (not too much) freon and oil, you might NEVER have a high pressure trip in your lifetime. You will probably blow a hole in a rusty condenser long before you trip the hp switch. If your compressor is are leaking and your compressor is frequently cycling....its probably the low pressure switch doing its job. If your compressor currently engages...disconnect the hp switch connector , the compressor should disengage. If your jumper the tan-ish wire to the light green with the ac on ...the fan should run. No way to test if the high pressure switch actually works without some complex test equipment. Since he had the fan side jumpered and i assume it was connected to the switch, just not hanging there?...the pins on the switch might be bent or damaged. Look in there with a mirror. The pictures are nut that clear...did he jumper both greens together?....serves no purpose at all. Whats up with the blue wire...looks like that goes somewhere its not supposed to...you may have to some detective work to figure out his hotwire butchery

 

I think the cooling fan on these years only turns on at temp, not with the ac like the older models.

 

That is correct, normal ops is temp only.....until you trip the ac high pressure switch.

 

The green wires appear to be jumped together - blue wire seems ok (the blue around the plug looks like a rubber gasket or something). I'm going to look up part number for the High side switch, pull it and replace, yank the jumper wire and see if everything functions properly. Feels relatively low risk based on everything i'm hearing here.

 

Like i said earlier..original po didn't know what he was doing....jumpering green wires does absolutely nothing