A/C holds charge, but doesn't cool

Hi all,

So, my A/C reads about ~40 PSI on the lower port, which is correct for the ambient temperature. Still blowing hot air. I got the above reading from a recharge can I got from Walmart; I know you are supposed to have it vacuumed, etc. but my mechanic's machine is broken, which led to a more ghetto solution. There is a lot that could be wrong otherwise:

1. the condenser is dented from an accident by the previous owner.
2. the temperature knob in the cabin does not spin at all. It's possible that it's stuck on the hot setting, although you would think this would be a little bit cool even with the A/C on. The A/C button does glow green.
3. it's not throwing any codes; not sure how to test the compressor otherwise.

Thoughts? My windows are not going to cut the mustard when it starts hitting triple digits around here!

 

I'd say start there just to be sure. May have some linkages/levers gummed up or jammed.

 

Question #0: Did you bother throwing gauges on it to check pressures BEFORE you put anything in it? (Make sure you don't fuck anything else up)

Question #1: Is the clutch even engaging/disengaging when you kick A/C on and off?

Question #2: Did you pop off the blower motor resistor to see if the evap coil is getting cold at all?

Question #3: Did you check to see if the blend door in the dash is broken, since it's known to happen?

 

I immediately thought blend door, but if that knob is stuck on hot, it won't cool it at all.

 

That was kinda the thought flow above, starting at step #2.

-> If the A/C clutch is visibly is not engaging/disengaging, coolant isn't being compressed, thus cooling won't be happening
-> If it is engaging/disengaging, that means the pressure switch thinks all is copacetic, i.e. it's charged enough, thus cooling should be happening, and the evap coil should feel cold, I believe?
-> If evap coil is cold, and the blower motor is clearly blowing, it's either control/broken blend door related.

Knowing you can overcharge stuff and fuck things up, I'd personally have checked my Question 1 / 2 items first before trying to use a kit to charge it ... but I assume the recharge kit had dye in it, so it may help with finding a leak if one exists.

 

Yes and yes to 0 and 1, which leads me to suspect that NickB is correct. Regarding 2, where is this located? From Google, it looks like it's a small, 4 pronged connector with some plastic; might be in the cabin someplace. Evap coil is...a black box made by Denso in front of the brake booster? I will see if that's getting cold.

https://www.youtube.com/watch?v=A1ivBNr8ZzY

Above tutorial shows that it's pretty easy to access the guts of the cabin controls, might replace these parts if I can find them online (few junkyards nearby).

 

Read this reply: https://www.tundras.com/threads/wha...-gen-tundra-today.2558/page-1571#post-3126837

If that's not clear enough on location, see this follow-up a few replies down: https://www.tundras.com/threads/wha...-gen-tundra-today.2558/page-1571#post-3126873

Start there. And heed the warning, the ceramic block can be brittle. Gentle, it's old. It's OK if it chips or cracks, you just don't want to break it to bits.

Also, have a vacuum ready to clean out behind it.

 

Awesome, thanks. Will report back in the next few days.

 

OK so I pulled the climate control panel. The fan switch speed still works but with the other two, the gears are frozen in place. I was able to manually yank the temp knob over to cold (actually the little cable in the back that controls that). The defrost knob has lost its connection in the back - any guides out there to repairing this? It might come in handy. But for the moment I am fine with jerry rigging it to where I switch it to heat in the winter and A/C in the summer by pulling the panel and just controlling things with the fan speed knob.

I don't know if that fixed it, but that was at least an issue. Will check it soon when I go out later.

 

Freon......not coolant.......

also, should of just taken it to a a/c pro. A/C systems are sealed. So if your freon go "bye bye" there is likely something else at play.

If the can-o-shit you used had the UV dye. Get a black light and looks around and look for the leak.

also how many lbs of Freon did you add? Most the of the 134a systems I've worked on are quite sensitive to how much Freon is in the system. Too low and it doesn't cool enough, too high and it won't cool at all and an over filled system leads to very quick compressor failure.

Id seriously recommend just taking it to an a/c specialty shop. Most of the customers my dad had come in were the guys who went to autozone and wound seriously fucking up shit up ( When it was just a $100 hose and a $75 recharge) wind up having to throw down $1500 to get their compressor and lines replaced and the recharge done properly.

 

So far, so good, even with the scummy and improper recharge. It's blowing ice cold now. If leaking, it should stop working at some point as the R134a leaves the system I would imagine.

 

Say what?

​

 

And our trucks don't take "Freon". Freon is a trademarked name for other coolants. I believe our trucks take 143a, which is Trifluoroethane.

 

134-a

 

That's one way to highlight a dude's dyslexia

 

Freezon

 

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