finding the low side a/c fitting

I have a 96 XJ and the a/c isnt very cold, it was last year, but there must be a slow leak. it is factory R134A i want to try to recharge the system but have never done it before, so i need as much advice/ help as possible. first thing is i need to know where the low pressure side fitting is located. also, my blower motor doesnt work unless it is set to "high" is it a bad switch? or something else?

thanks!:wave1:

The blower switch is probably fine, the blower resistor however is most likely the cause of your problem. These get hot and sometimes melt the connector so good luck getting it off.

so basically i would have to get another switch assembly? i can get one from a bone yard i dont have a problem with that. but what about the a/c? which side is the low pressure side? :dunno:

Large hose is low pressure (suction side). Low pressure fitting will be someplace on this line, near the compressor.

It could be the fan switch itself, the blower resistor(s) pack, or both on the fan speed. The low Pres. fitting is between the compressor and the expansion valve on the firwall, and it is typically the larger diameter hose. Sometimes the hoses have the same OD (aftermarket stuff), making it hard to tell from hose diameter alone. Also, the fittings on the hoses ( HP & LP) are two different sizes, so you can not accidently attach a refrigerant can to the high side and :gonnablowit up.

Thanks for the replies! i checked and the compressor isnt even coming on when i put the a/c on to max so i am hoping it is just it is so low on freon it wont let the compressor kick on. now i have another question, how many cans of R134A do i need?:confused1

suprz said:

Thanks for the replies! i checked and the compressor isnt even coming on when i put the a/c on to max so i am hoping it is just it is so low on freon it wont let the compressor kick on. now i have another question, how many cans of R134A do i need?:confused1

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Start with one can that includes leak finder dye in the can. Let the system suck gas in while the compressor runs (keep the can right side up, may take 20 minutes to empty the can), then look for dye leak, and see what happens (if there is a visable leak) while the A/C runs.

Then go from there. Being a 96, it is probably time for new AC hoses. When those get changed you need to change the dryer to, and the o'ring seals on the ends of the hoses. Then you need a vacuum pump to pull a vacuum and get all the air and humidity (water) out of the system, then it needs a fresh recharge, with a dab of oil to replace any oil that was lost in replacing the parts. Point being it is probably time to take to a pro and get a new set of hoses. I use an aftermarket A/C shop that makes their own hoses. Lot less expensive than the Stealership for A/C hoses. You get HOSED at the stealership, if ya know what I mean.

If you do not find a leak with the dye, and the A/C runs for a while, then go get a set of gauges (DIY) and check the high and low side pressures to if it needs any more refrigerant. There is slim chance it just slowly leaked out over the years.

suprz said:

If i hook up the R143A and start to put it into the system, will the compressor start to run once there is enough pressure? I know the compressor should be running and the system should be on max cool, but in my case the compressor isnt turning and im hoping it si due to low pressure in the system

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If your problem is low refrigerant, then yes the compressor will engage once the can of refrigerant is attached to and opened to the low side fitting.

And, if you look at the back of the compressor, you should see an "S" and a "D" next to the ports - "S" for "Suction" (low pressure) and "D" for "Discharge" (high pressure.)

Make sense?

The blower resistor is the "speed control" pack - it's not directly behind the switch. I don't recall where it is offhand, but it's probably down by the plenum or over near the blower fan motor. You wish it was near the HVAC controls...

5-90 said:

The blower resistor is the "speed control" pack - it's not directly behind the switch. I don't recall where it is offhand, but it's probably down by the plenum or over near the blower fan motor. You wish it was near the HVAC controls...

Click to expand...

Look near your feet, on the passenger side, under the dash, for a 4 wire push on connector, it is attached to the resistor pack which is attached with two screws to the Evaporator box. The air flow also cools the resistors, but they also rust out from condensation (when on A/C in humid climates) over time. My 85 pack was a pile of rust.

It is about $12 at the dealership. OEM only. Not available as an aftermarket part (that I could find anywway).