# Toyota Truck AC Compressor



## BigJim (Sep 2, 2008)

I have a 1990 Toyota V6 SR22 4X4, the AC clutch won't engage this year for some reason. I thought it needed refrigerant but it won't hold any more. I checked the fuses (unless there is one I don't know about) and they seem to be OK. Is there a way to by pass the switch to see if the clutch will engage?


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## djlandkpl (Jan 29, 2013)

If you can find the pressure switch unplug it and put a jumper between the wires on the harness.


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## BigJim (Sep 2, 2008)

Thanks, I will see if I can find it.


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## ukrkoz (Dec 31, 2010)

1. If you over fill the system, safety kicks in and clutch won't engage
2. you can jump pressure switch ONLY to test clutch function. ONLY. And for SHORT period of time. As because if your system is low on freon, it's low on compressor oil also. You'll seize compressor in no time.


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## BigJim (Sep 2, 2008)

That is really good to know about jumping, I will for sure keep that in mind.

I may have over filled it. While I didn't draw a vacuum on the system, I couldn't get it to take more than just a little. I do know the clutch will not kick in, but I can't remember if it did before I started adding to the Refrigerant or not. I will check to see if I can jump the wires to see if the clutch will click. I appreciate the information.

Just had a thought, I can't say any refrigerant went in at all, if the compressor wasn't working, then the refrigerant didn't go in, right?


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## ukrkoz (Dec 31, 2010)

Well, thing is, you can NOT refill the system if compressor does not work. Hence, you have to jump the switch, to trip compressor, to suck freon *OIL MIX* in. Never add freon only.
But you do this in short bursts, and need 2 people - one to refill and one to turn a/c on and off. refill in about 5-10 top second intervals. 
Modern cars go by freon WEIGHT only, yours is easier in that respect for the year.
Also, it's converted to 134, right? As it's likely old freon, and 134 gumms up when it reacts with old freon.


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## BigJim (Sep 2, 2008)

ukrkoz said:


> Well, thing is, you can NOT refill the system if compressor does not work. Hence, you have to jump the switch, to trip compressor, to suck freon *OIL MIX* in. Never add freon only.
> But you do this in short bursts, and need 2 people - one to refill and one to turn a/c on and off. refill in about 5-10 top second intervals.
> Modern cars go by freon WEIGHT only, yours is easier in that respect for the year.
> Also, it's converted to 134, right? As it's likely old freon, and 134 gumms up when it reacts with old freon.


I really do appreciate the information. The compressor must not have been working because it wouldn't take freon, like I thought it was. 

I may have a problem, I took for granted that the former owner converted to the new stuff and he may have, I really don't have any way of knowing. If I did mix the two, what is the worse case scenario. What should I do to make sure or how could I find out?

It worked fine since I topped it off two years ago, this year the clutch just won't click in.


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## ukrkoz (Dec 31, 2010)

Well, then you might have gotten lucky - or, that's exactly what happened, system gummed up on you. Old freon and 134 do not mix well.
Once again, you can not simply push freon/oil mix into the system. Comp must be working to virtually suck it in.
The only solid way to do this all is to have her leak tested. Then, they fix the leak, purge system with cleaner, and retrofit with 134. 
If you have leaks, you'll keep tossing money at it forever.
But if you jumped the switch - it's usually in that large shiny cylinder can, next to firewall, keep forgetting its name - and a/c comp did not kick in, then you have issue place else. Like tosted clutch, Or, simply disconnected clutch plug or no power to it. Or blown fuse.


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## BigJim (Sep 2, 2008)

That is some good information, I will check it out, may have to have a tech on this one. If the two are mixed, will a shop service it, I am not sure they will. Thanks for all your help, I really appreciate it.


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## ukrkoz (Dec 31, 2010)

You welcome. Shop will run cleaner through 1st. But if it's blocked, or leaking, no shop will work on it, unless parts are replaced.
Suddenly, you start looking at expensive adventure, unless you DIY repairs.
So you need to find out few things 1st.
1. does comp clutch have 12V to it? When a/c is turned on?
2. if not, likely due to low pressure, can it be jumped off a battery, to check on clutch function?
3. is the a/c belt tight?
4. buy set of gauges, not that expensive. Check system pressure.
5. for 1990 model, chances are, you still on old fittings, but they do have adapters for those.
6. locate pressure switch. Apparently, in Tacomas it's mounted on Low line, 2 wire switch. Do not attempt to remove, he-he, as it will let all freon left over into the skies. You shorten the connectors that come out of it, after plug removed. If clutch kicks in, THEN you can load freon/oil mix.
Otherwise, your clutch is toasted and does not spin comp.


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## BigJim (Sep 2, 2008)

ukrkoz said:


> You welcome. Shop will run cleaner through 1st. But if it's blocked, or leaking, no shop will work on it, unless parts are replaced.
> Suddenly, you start looking at expensive adventure, unless you DIY repairs.
> So you need to find out few things 1st.
> 1. does comp clutch have 12V to it? When a/c is turned on?
> ...


I have this information saved so I can copy it and have it this week so I can give all this a try. Our ole truck is a SR22, if that makes any difference of where the switch is located. The way my luck runs I can just bet on it being the worse case.

If it don't rain this week, I hope to check it out. I will let you know how it goes, thanks again.


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