Summer's here and my truck's AC is still broken. The light in the AC button turns on but no one's home. My truck is a 1987 Toyota with the 22R. Its not so bad here along the southern California coast but I like going places that tend to be hot/dusty. Just to be clear, this is the first time I've ever attempted to fix an AC system instead of just ripping it out. Thus far, I've determined that the compressor clutch isn't engaging. The FSM told me to check the resistance of the stator coil. Spec is 3.7 plus or minus 0.2 ohms. I got 9.3 ohms meaning I need to replace the coil. Is the coil part of the clutch or what? Also, what else should I be checking?
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July 9, 2010 5:34 p.m. thatsnowinnebago Dork
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July 9, 2010 5:42 p.m. BoxheadTim Dork
I think it is - you probably have to replace the whole clutch or somethin'.
I'd also get the refrigerant checked to verify it's not low on refrigerant as most compressors shouldn't kick in if there isn't enough refrigerant in the AC.
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July 9, 2010 6:24 p.m. m4ff3w SuperDork
Jumper the low pressure switch (or just feed 12v to the clutch).
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July 9, 2010 7:04 p.m. thatsnowinnebago Dork
I'm not real sure how to do either of those things.
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July 9, 2010 7:37 p.m. ignorant SuperDork
If you are low on refrigerant it won't kick on.
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July 9, 2010 8:18 p.m. Tyler H Dork
There is one wire that goes to the AC clutch. Run a jumper to the positive lead of the battery and listen for a 'click' and look to see if it locks up the AC compressor pulley. If it does, the clutch is fine.
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July 9, 2010 8:21 p.m. thatsnowinnebago Dork
Tyler H wrote:
There is one wire that goes to the AC clutch. Run a jumper to the positive lead of the battery and listen for a 'click' and look to see if it locks up the AC compressor pulley. If it does, the clutch is fine.
Oh that's not so hard. Thanks
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July 9, 2010 8:30 p.m. Tyler H Dork
thatsnowinnebago wrote:
Tyler H wrote:
There is one wire that goes to the AC clutch. Run a jumper to the positive lead of the battery and listen for a 'click' and look to see if it locks up the AC compressor pulley. If it does, the clutch is fine.
Oh that's not so hard. Thanks
If the clutch is good, either the low pressure switch is doing its job and the refrigerant is low or there is a problem with a relay or some other component.
Alternatively, you can check for voltage on the clutch wire while the engine is running with the AC switch on.
If voltage is present and the clutch isn't locking up, then it is bad.
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July 10, 2010 9:30 p.m. curtis73 HalfDork
Quick primer...
Juice goes from the dash switch to the low side switch, the high side switch, and often times an evaporator temperature switch before going to the compressor clutch. Those switches are all in series, so a fault at any one of them will shut the compressor off.
Of course, depending on the vehicle, the real power comes from a relay or a small controller, but that is the basic path of the juice.
If you haven't already, convert it to R134. To do it the "right" way you'll need to change a ton of stuff, but there is nothing wrong with doing it the "dirty" way. Buy the adapter valves at Auto Zone, have a shop reclaim the R12, and charge it with R134. It won't get as cold, but it will work.
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July 10, 2010 9:39 p.m. thatsnowinnebago Dork
curtis73 wrote:
Quick primer...
Juice goes from the dash switch to the low side switch, the high side switch, and often times an evaporator temperature switch before going to the compressor clutch. Those switches are all in series, so a fault at any one of them will shut the compressor off.
Of course, depending on the vehicle, the real power comes from a relay or a small controller, but that is the basic path of the juice.
If you haven't already, convert it to R134. To do it the "right" way you'll need to change a ton of stuff, but there is nothing wrong with doing it the "dirty" way. Buy the adapter valves at Auto Zone, have a shop reclaim the R12, and charge it with R134. It won't get as cold, but it will work.
My plan does involve doing the conversion the "dirty" way. Any cold air is better than just a fan.
