Help with A/C trouble shooting

I have a 2001 tacoma with the 5vzfe. I lost my AC a couple of years ago and finally decided it was time to diagnose/trouble shoot. I have had, for a while, a loud sharp squeal on cold start up that goes away after a few minutes. I suspect this may have something to do with it. My compressor will turn by hand but does not engage.I thought maybe I was low on freon and wasnt reaching the pressure threshold so I got a set of gauges, a vacuum pump, and everything to do a proper recharge. When I hooked everything up I had a reading of around 80 (I think, I should have taken a picture) on the low side and maybe 10 on the high side - Which should be plenty of pressure to kick the compressor on.

I then thought that it may be the dual pressure switch. To test this, I put a hot wire from the (+) battery terminal directly to the compressor wire - which I would think bypasses the switch. Again, it did not engage. The A/C button on the dash lights up, all fuses are intact, AND the engine idles up when the A/C button is pushed. So Ive narrowed it down to either a bad clutch or a bad compressor. Is there anything that I'm missing that could be tested before I drop the money, time, and effort on swapping out the compressor?

I guess I should add that I did have the system Evac'd and I tried to recharge but the compressor never kicked on.

Thanks in advance

 

Check this for some troubleshooting steps. You can buy the AC clutch seperately on ebay and Amazon. Hope it helps, it's too fucking hot to not have AC..

 

A little update. Pulled a vacuum on the system around 5pm yesterday and left it overnight. Looks like it held vacuum successfully. So it's looking more and more like a bad compressor I think

 

Thanks, I have the FSM but it's a bit difficult to follow. Is there any benefit that you know of to just changing the clutch? Seems like for the work and the cost I may as well swap out the whole compressor.

 

I've changed a couple of AC clutches and they are pretty easy, and a lot cheaper than the whole compressor. I wouldn't gamble on just throwing parts at it without doing some testing to narrow down if it's the compressor, the clutch, or a wiring problem. The FSM section has some simple tests to check the wiring.

You said you heard noises. That could be belt slipping, clutch locked up, or compressor seized. But you said the pulley spins, so maybe the clutch isn't bad or maybe it's intermittently bad, you should be able to single out the clutch and activate it then try spinning the compressor. Which it sounds like you may have done but I wasn't clear on your outcome.

 

I guess my point is that the best price I've found on a new OEM clutch assembly is $150 shipped. A new Denso compressor w/ clutch is $219 on Amazon. If I'm going to go through the trouble of removing the power steering pump and pulling the compressor to replace the clutch, why not just throw a new compressor on to avoid having to do it again if the compressor is damaged.

I'll admit that electronic diagnostics is a weak point for me, but it seems that hot wiring the clutch to the battery should cause it to operate if it weren't the issue, especially since it idles up when the AC button is pushed, the blower works, and all fuses are intact. Is there something that I'm missing?

 

Does hot wiring the clutch not single it out? The compressor spins by hand with the engine off

 

That's what I was saying I wasn't clear on your results. I don't know if the clutch is released(pulley free spins) when hot wired or engaged(locked to compressor). The clutch could probably, maybe not easily, be replaced without removing it but if you ruled it out then it's moot. Are you sure the compressor is spinning by hand and not just the pulley?

If the compressor doesn't engage, but as above does spin, then I would think it's not the compressor. The engine idling up may be the computer getting the signal to idle up, but seems like the compressor isn't getting the signal. Points me to a wiring problem.

 

Disregard everything I have said to this point, I guess. I just retested the clutch and it works. This time I removed the connector from the compressor and attached an alligator clip to the pin on the compressor side, then the other end of the wire to the battery and the clutch locked. So hopefully its just a faulty connector. I'm going to test it for continuity. I guess if the connector is good, then there could be an issue with the wiring more central to the main harness?

 

Ok, another update. Even though the connector showed continuity and the wire from the truck did as well, the compressor would not cut on unless it is hard wired. I was able to charge the system with the compressor hard wired to the battery. I have ordered a replacement connector. Hopefully that was the problem

 

That's progress and before the hottest part of the day!

 

Yes to the wiring... I looked at my free website for a correct wiring diagram and there is nothing. My factory manual is for the 98 model year. I cant imagine toyota changing the wiring for the AC that much between the years. I will see if I can upload some pics later today, unless someone can upload/link the correct diagram.

 

What out buying parts from Amazon, everybody telling counterfeit parts. Should look at local parts store if get Denso a/c compressor. But up to you.

 

This appears pretty common, I've had it (it drove me nuts for moths.) It will be the alternator belt needs to tighten up a little.

 

Thanks for the heads up! Hopefully this $6 connecter is the culprit!

 

Yeah, I should probably change out all the belts and the idler pulley. Ive had the truck since 2020 I think and havent done that yet