Need a how-to on A/C low pressure switch jumper

Short bit of wire. You just connect the two wires that went to the low side switch to each other.

Start the car, turn the AC on full/MAX, then jumper the two wires. That will trick the system into thinking you have a full refrigerant charge and if the ac compressor clutch kicks in, then it's a fairly sure sign your low on refrigerant.

Do not run the system like this for more than a few seconds, it can starve the compressor of oil. Jumpering the low limit switch is not a fix.

Your 01 is going to use R134a, they sell cans and pressure gauge sets in most stores. The thing is you need to find out what is leaking. It could be just a bit low (all systems leak a bit) or something is loose. Look for dirty oily spots around all the fittings.

You can get a basic pressure kit (looks like a tire pressure gauge), a gauge on a can (get the reusable one), or the full up high/low side set. By the way, never charge from the high side, the can will pop.

This is a fairly good site.

Advantage of those quick&dirty refill cans is that they usually come with a dye added. Most of the dye is pretty easy to spot in daylight but a UV light source makes it a snap. Takes most of the question of "do I have a big leak" out of the equation before you blow the money on a full charge. Seems like the last half dozen or so I've seen have been at the end of the hose around the swaged fitting, at least on newer systems. Of course, mine had to be at the head gasket on the compressor.....

This is too, for tools, manuals, parts and supplies.

Earle

** Posted from **

Thanks all for the replies... It's been a LONG time since i have frequented this board (mainly due to all the spam on it) It is good to know the same guys are still on here... I figure I'll give background... Maybe this is sometime i need to take in.. but i have prided my self on doing EVERY piece of work on my baby up until now and i would really hate to have to pay someone to fix it (a pride thing)

Over time.. the ac had been making noise when i was idling at a stop... if i turned the AC off at the stop it would stop making noise... if i started it again.. noise would re appear... but if i was moving.. the noise was not there and i would get full AC cool air... then one min it was working then the next it was blowing hot air (it is in the 100s here in texas)

So first thing i did was to check the freon level.. when the system is off and jeep is off the psi read abouti 110 psi (on the low side) when the system is on.. the reading was a little higher.. 120s or so... (note: i have never added freon but i do have a canister of

134a just in case)

The low pressure line (which is usually very cold to touch, is now actually hot and the high pressure line is ambient temp

When I turn on the A/C i can see the clutch engage and the compressor spins and the idle on the car flux a little but.. (maybe 100 rpm for a sec or two) and i hear a new noise (assuming its the compressor working) but it does not cycle on or off.. just runs...

Last night I did the jumper of the low pressure switch and it did exactly the same thing as if i flipped the AC switch in the cab...

So at this point I am stumped.. I have read that if the compressor isnt working that there will be about a 100psi reading on the low pressure line.. but i can heard and see the compressor engaging....

thoughts?

Thanks all Kurt

01 TJ sport 3.5 inch teraflex w/ 33.5 Procomp MT