A/C stopped working today, need help

[jseabolt]

The other day I connected a set of guages to my 96 Explorer.

I felt as if the system was not cooling as good as it should be. Mid to upper 90s outside, 54F on A/C and 45F on MAX A/C. My Subaru will put out 45F air on fresh air mode.

The guages read 30 PSI on the low side and 180 PSI on the high side. So I connected this "tool" a friend let me borrow to the low side and it said "add refrigerant". In the meantime I just left the system alone.

Well today the A/C started acting funny. Like it was cooling sometimes and sometimes it wasn't. Well tonight it just finally just quit.

I popped the hood and here's what's going on. On MAX A/C, the compressor is cycling on and off every 1 second.

So I try adding a can of 134a. The instructions say to add refrigerant until the pressure guage reads 40 PSI. Yeah I know your supposed to take the vehicle to the Ford dealer and have the old refrigerant sucked and then the proper amount added per ounce instead of going by PSI but..

If I squeeze the trigger, the guage reads about 5 to 10 pounds. If I let off the trigger the guage reads about 150 lbs. I'm guessing the 150 lbs is the can pressure and not the actual system pressure.

The problem is even after 15 minutes, the can is still full! So apparantly no refrigerant is being sucked into the system.

If disconnect the low/high pressure switch from the reciever (or accumulator), the compressor quits cycling.

The other day I recharged my Fiat 131 after putting the system back together (totally empty) with no problems but my Explorer is giving me a fit. With the Fiat as soon as I opened the can the compressor kicked on.

I read that if the compressor won't kick on, your supposed to run a wire to the compressor from the battery to bypass the low/high pressure switch. Due to the design of connector on the compressor this sounds easier said than done but it would be much easier to just unplug the low/high pressure switch and run a jumper wire across the connectors there. Is that a good idea? Or would that not do the job?

What's causing the compressor to cycle on and off ever 1 second? Looks like if the system was too low on refrigerant, then the low pressure switch would prevent the compressor from kicking on all together.

Have I got some other issue going on here instead of low refrigerant? I'm just assuming that's what it is based on the guage readings the other day when the system was working.

 

[firepop5]

That should do the trick. Jumping the reciever plug (you can use a paper clip) should allow the compressor to run and suck in the 134a. Try removing the jumper and putting the plug back on after the can is half empty. Are you on the Fiat website also? I have a 96 explorer and an 85.5 Pininfarina Spider

 

[jseabolt]

I tried the jumper wire trick and managed to get 2 cans in the system but only raised the pressure 5# on the low side to 35# but the compressor still cycles on and off every one second.

I've got much colder air now. It was between 80 to 85F today and the air coming out of the vents was 28F!! That's about 20 degrees colder than what it was before adding 2 cans.

That may actually be too cold because I think at that temperature the evaporator would ice over like my heat pump does when the filter get's dirty. That's when I know it's time to change the filter in my heat pump!

I stopped by this A/C shop that is supposed to be the best in town and the guy said, "OH NO!! Don't run your A/C until I look at it, there's some reason why your compressor is cycling on and off (bad pressure switch?) and you may have put too much in the system. It may not have needed any refrigerant to begin with. Your condensor or evaporator may explode, where ever it finds a weak spot".

Of course they are going to tell you they are the only ones who can service an A/C system because that's how they make their money.

Just like that guy that charged my dad $500 to repair one side of the brakes and I turned around and fixed the other side for $40. Long story on that one.

They he's like, "Well back in the olden days with R-12 and sight glasses you could throw in a couple of cans until the bubbles were gone and you knew the system was full, now you have to have these fancy expensive computer machines that suck what's in the system out, measure it and put in the correct amount per the manufacturer"....

Refrigeration is still based on evaporation, how hard could it be?

I think the reason R134a is so expensive is so Joe Blow's like me won't vent the stuff to the atmosphere. I remember when antifreeze was $2.99 a gallon and R12 was $1.00 a can.

Use to if you were changing a thermostat with "good" antifreeze it wasn't nothing to just let the stuff hit the ground and lay a water hose down so it would dillute so cats and dogs wouldn't drink the stuff. Now it's too expensive to do that.

Oh well. I still don't know why the compressor keeps cycling on and off with the pressure switch bypassed so I guess I'll drop it off at his shop after getting off working Friday morning so he can take a look at it. What a PITA.

That's why I like working on my cars myself so I don't have to get a ride or sit around and wait for someone else to fix my car.

 

[jseabolt]

I meant to give you guys an update on my A/C problem. Sorry. Read above for the details.

After putting two cans of refrigerant in and only raising the low side pressure from 30# to 35#, the A/C still didn't work right. So I took it to an A/C expert.

I didn't get to talk to him after the work was done but on the bill it said:

Replaced orfice tube
Replaced low pressure switch
Removed too much refrigerant.

The bill came to $132. I was not happy considering he probably only did 2 to 3 hours of work at the most. If you bought the parts from NAPA they would have totaled about $20. And he kept the two extra cans worth of R143a ($20).

I guess you pay for experience. That's why I do my own brake jobs.

The A/C is cooling much better now (about 15 degrees cooler) but my god, how can someone justify charging someone $132 for the amount of work he did?

If I had known what was wrong with it, I would have just vented the stuff to the atmosphere, replaced the parts, pulled a vacuum on the system and recharged the system myself. I could have refilled a bone dry system three times for what he charged me. Yeah, I know...

Based on what I've read anything less than 40# means the system needs recharging but according to him a clogged orfice tube will do the same thing.

Funny thing though. A co-worker has a Chevy truck and he said his orfice tube was clogged on his truck but he was getting too high readings on the high pressure side. My high pressure side was in spec. In my case, the low pressure side was too low.

Any thoughts on that last one?