kpayne111

Hi all, I just bought an 04 TL about a month ago. This is my first Acura (and first forum post) and so far it's been a pretty good car. A week after I had it I started having an issue where the AC blows pretty cold at idle, but when I'm up to speed for a bit, it stops blowing cold. I checked the low side pressure with a gauge (I know I need a proper hi/lo manifold set), and it was at 60psi when running and topped my gauge out at 150psi when off. I assumed this was overcharged so I drained it down to 80psi off and 50psi running. This still seems too high, and a couple of days ago, the AC now doesn't work at all but has pressure. Any ideas what the problem is? Also, what pressures should I be seeing with the AC on and off? Thanks!

01acls

AC problems are hard to diagnose and impossible when the poster don't provide ambiant temperature. That is because ambiant temperature and AC pressure are related. Like you said it requires both hi and low readings for proper evaluation.

My guess is you are low on freon.

kpayne111

Ambient temps were in the 30C range, which usually means ~40psi from what I can see. I thought i would have enough pressure to at least engage the clutch. I'm starting to wonder if the compressor is going out or expansion valve is stuck open. I suppose I can just put in a can of freon and see if the compressor starts engaging again

01acls

Without the hi pressure reading it's hard to narrow down. Your choices are low on freon, air in the system, bad compressor/control valve.

Ken1997TL

I'd bring it to a qualified A/C technician who can diagnose it. There are many possibilities and you end up throwing unnecessary parts at a symptom rather than the real problem. Been there and done that!

kpayne111

I'm wondering if there is just air in the system, hence having pressure but compressor no longer engaging. It blew Cold air before I drained it, but weird how it has a lot of pressure in the system but isn't working. Is this possible?

01acls

There is no air in the system unless the system is empty, has leak or someone introduce air into the system when adding freon.

kpayne111

I tried draining the system of any pressure and refilling with a can of freon. I can't get the compressor to engage. I'm thinking either the compressor clutch has gave way or the car wont let the compressor engage for some reason. What terminals do I jump to see if the clutch works?

01acls

I don't have a schematic for your ac so I couldn't tell you which wire to jump but the ac clutch only has 1 or two wires and one will be the positive trigger wire.

I don't think your problem is mechanical in nature. Seems to me it's operator error. You introduced air into the system when you drained all the freon out and try to equalize the system to atmospheric pressure. Atmospheric pressure is air pressure. When you fill the AC system did you vacuum the system and purge the freon canister fill hose of air?

I don't think one pound of freon is enough for your ac system.

kpayne111

I did not vaccuum. I bought a small can of freon just to build up pressure and introduce some in the system to see if it would kick on. It got up to 90psi and nothing is happening, if anything it should have at least tried to run briefly. If I can't get the compressor to run when jumping it then I found my problem. It's possible that the compressor was on it's way out from the getgo, hence why the ac would shut off.

01acls

Yeah unfortunately without a base line reference of no air in the system and with proper amount of freon in the AC system it's really just speculation. I speculate you have air in the system and it's also low on freon.

Get it vacuum out and refill. You might get lucky. Either way they will tell you if you have a leak or what.

kpayne111

It has 90 psi in there. Shouldn't that be enough to make the compressor try to cycle regardless of air or low freon in the system?

01acls

90 psi is about right for a static ac system at 30c. That is definitely enough pressure to engage the AC clutch.

The other thing that can cause the compressor to lock up is introducing liquid freon in the intake of the compressor and damaging the valves but you should still hear the clutch cycle on/off.

You should check for a hot at the clutch wire. Under the hood fuse block, look for a snow flake symbol, that should be the AC relay location.

kpayne111

I tried jumping the ac relay tonight and it isnt engaging the clutch. There aren't any sparks or anything, so either the clutch is shot or for some reason the compressor isn't getting power

Ken1997TL

What is the evaporator temperature sensor doing?

On my RL, it thought the evaporator was much colder than it was and prevented the compressor clutch from engaging.

kpayne111

I haven't tried that, how can I check it? I've been assuming it was the field coil/clutch. I've been trying to locate pressure switches too, no luck yet.

peter6

Sensor #5 should be the thing that Ken1997TL is talking about.




You checked the under-hood fuse #12 right?

Like rest of the people mentioned, get to the AC compressor clutch plug and test if you have a good ground and have a signal when AC "should" be running. That's most of the time second step right after checking the pressure/amount of refrigerant.

kpayne111

I just checked the evap sensor and fuse, both are good. looks like I have to do some digging to get at that connector, oh boy

peter6

Can't you get to it from the top? Never did a compressor in TL so no idea but I imagine the wire goes from the top, somewhere around alternator cable, and then splits to AC and rear of alternator.

kpayne111

Quick update, tested the field coil and it was no good at all. Managed to get a compressor with a decebt coil on it from a junkyard (resistance was a tad high but actuates fine with power on it.) currently in the middle of taking off the coil on my car and will be swapping in the new one!

kpayne111

Well I finally have ac again! Swapped the coils and blows ice cold

kpayne111

Well that didn't last long. After about 20 minutes I smelt a hot metal smell, popped the hood and looks like the new coil was too weak, slipped the clutch and eventually went. That's the last time I go to the junkyard for an ac compressor

thoiboi

You pay what you get for

peter6

You can have a kit for $50 from ebay, and since coil and clutch is not a rocket science, I would trust that kit more than used compressor from junkyard.
(something like: https://www.ebay.com/itm/AC-Compress...pe!60091!US!-1)
(they even come in "racing red" lol)

Additionally, there should be couple washers under the clutch which are used to set a gap. When clutch is used a lot, it might wear out enough to allow slipping. Maybe that's how your overheated?

kpayne111

I've actually had really good luck with junkyard parts on a lot of my family's cars, but this was my first time trying out ac stuff and I guess my luck has run out.

I know the washers you're talking about. There was one in both compressors, the gap was pretty tight actually. I think the coil I put on was just on its last legs and just a little slippage was all it took to kill it.

Thanks for the link for the clutch! But damn, 50$ shipping to Ottawa, maybe I'll try shipping it to the ups store in ogdensburg.