1990 22RE 4wd manual
so last year my AC was icy cold, today was the first warm day in a while here in SoCal so I tried the AC on my way home from work and it didn’t get cold at all. I figured it was the cable that moves the heater controller arm but I moved it to completely cold and it didn’t make a difference. So I started looking around the system since I needed to straighten my bumper anyway. (Had a rough nose landing a while back and twisted it cause the tire caught the corner)

The clutch will always engage when I click the ac switch. Light turns on on the switch. Condenser fan runs when ac is engaged (I jumped the plug to make it always run when ac is on for slow crawling in the summer) so I think everything is getting power. I pulled the plug on what I think is the pressure switch and checked the voltage (13.8v) at the plug with ac clutch running at idle. The pressure switch (I think) says 15.0-ON 12.5-OFF so maybe this is my problem?
pic of plug and switch in question



I looked in the site glass on the receiver dryer can thingy and didn’t really see anything. Kinda looked like clear fluid moving around? Might be empty tho? Didn’t see any refrigerant leaks anywhere but the junction into the top left corner of the condenser was a little moist, but not like dripping or anything. Can anyone help a yotabro out? Tried googling but can’t find an instance where there’s power everywhere and the clutch is working but it’s not cooling.

here’s a fun pic to help you help me


thanks yotatech

 

What does a refrigerant leak look like? (All refrigerants, and certainly the R12 that was probably in your system, are gases at standard temp/pressure. Nothing to see.)

Your most likely problem is "no refrigerant." Don't waste time (and kill everyone on planet earth) with the "A/C in a can" you might see in an auto parts store. You have to fix the leak.

So either take it to a place that does this for a living, or figure out how to do it yourself. Here's everything I know about air conditioning: https://www.yotatech.com/forums/f116...-r134a-284801/

 

Wouldn't the high/low pressure switch not allow clutch to energize if the system was empty?

 

that’s why my first thought was heater control valve cable. I’ll dig around the system a little more

 

Feel the tube feeding the evaporator from the condenser with the A/C on. Is it cold?

 

I’ll check that when I get home. Thanks!

 

The tube is cold. Air out of the vents isn’t tho. I pulled the glovebox off and blew all the crap out of all the ducts and doors and whatnot I could find. A lot of dust bunnies in there. Tested the fluid level per the instructions in the online FSM and there appears to be enough refrigerant in there according to the sight glass. Probably gonna go use my buddies gauges to test the pressure this weekend. Doesn’t make sense to me that the refrigerant pressure would be too low if the compressor is kicking on though.

 

Does it sound & feel like the door that bypasses the heater core close shut when you slide the lever to cold?

My evaporator was completely clogged up with dirt & dust and ended up cleaning with a couple cans of evaporator cleaner & compressed air. I would soak the fins on both sides, let it sit, blow it out & repeat over and over making sure the drain stayed unclogged. I tried one of those fin brushes to clean it but those fins are so thin & close together, it didn't really work. There are condenser cleaners & evaporator cleaners, do not use condenser cleaners. It wasn't that hard to do since I had the dash off and all ducts removed since I was changing the heater core at the same time. The evaporator box enclosure can't be removed completely with the evaporator still connected to the 2 lines, I tried every which way to remove it with no luck and no way I wanted to disconnect the lines with precious R-12 in there. Not sure how much more difficult it would be with the dash still in, maybe just removing the glove box will give you good access to the evaporator box?

However, I still had cool air even with the dirty evaporator, now it is just colder.

 

I pulled the glove box off yesterday to blow the stuff out but I don’t think I can get the evap box out with just the glovebox removed. I tried blowing the drain out and I think that’s clogged because I couldn’t hear the air blowing inside the cab so that may be a problem too. I extended the drain tube because the oem one was dripping directly on my hydro bump causing it to start rusting, but I extended it with clear tube so I can’t see any obstruction there, must be in that box. Guess if I put the gages on it and there’s enough pressure it must be that the evaporator is clogged with dust and crap? Wouldn’t be surprised if it was, there’s no prefilter for the air in these and it’s has a lot of dust and dirt over the years of desert trips. I’ll report back later this weekend after I test the pressure. This really has me stumped since everything seems to be working as it should but I’m not getting cold air. I think someone has definitely messed with the system before. The wires to the pressure switch near the condenser were routed goofy, and the evap box was missing one of the nuts that holds it to the dash.

 

I admittedly have not read this entire post thoroughly, but I did not see anything about the expansion valve may be the issue. See my build thread, bottom of page 19.

CLICK HERE: Bottom of Page 19