AC Cooling unit removal

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My AC only runs on high. Sounds like a common issue when the AC blower resistor goes bad. Looks like the cooling unit has to come partially out to get to the screws for that resistor. Do you have to discharge the refrigerant from the system in order to take the cooling unit out?
 
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I had this problem on my ‘94. Is was a relay that had burned. It mounts above the ac box and I think it is accessible by removing the glove box. I didn’t remove the ac box to fix it.
 
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Thanks for the reply. So are you talking about one of those two silver round thinks that set right above the cooling unit was your issue?
 
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Mine was a larger black relay box.
I’m not sure what year yours is. Here is a picture of the sub harness with it.
I got replacements from a junk yard.
372BF637-0B96-4CED-B6AC-45A2E9F68F7F.jpeg
918AB118-14FD-4498-AC3C-AD8E142D169B.jpeg
5370A80A-0B54-42DB-8F70-82907DB79BC1.jpeg
 
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Thanks for info. So your issue was the same as mine, ac only blows on high?
 
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Yes my blower was only working on high. I replaced that harness section as it was melted by the relay, and the relay also.
 
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I guess now the trick is to find the part. Appears to be another unobtainable.
 
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That 97 auto a/c system does not have a resistor pack or relay box. By the looks of the diagram, full speed is controlled by a relay and power transistor, and other speeds are controlled by the ac amplifier. Your issue may be the amplifier or the control unit sending the signals to the amplifier.

Maybe do a search in the 100 forum as they should have a similar system.
 
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Hmm, the FSM shows a blower motor resistor that screws into the side of the cooling unit. I found this picture from another tread that appears to be the part that corresponds with spot in the FSM.
1661125250213.jpeg
 
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It seems like the typical setup is all speeds go through the resistor except high. It’s a pretty common issue with all kinds of makes and models. There’s a couple other examples on here of it being the resistor. I figured I would change it out and see, but can’t seem to find the part anywhere, nor the relay mentioned above.
 
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It seems like the typical setup is all speeds go through the resistor except high. It’s a pretty common issue with all kinds of makes and models. There’s a couple other examples on here of it being the resistor. I figured I would change it out and see, but can’t seem to find the part anywhere, nor the relay mentioned above.
In the previous 2 ac iterations on the 80, that is correct, because they use a resistor pack with multiple resistors for multiple speeds (low, m1, and m2), but your setup only has 1 resistor (hence only 2 wires). The way i read it, high goes through the relay or transistor, low through the resistor, and m1 and m2 through the amplifier. Toyota really overcomplicated it for this auto system.
 
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Oddly enough, all speeds were working on the drive in this morning. All I did this weekend was pull the glove box and the AC amplifier to see that the resistor was in a spot where I couldn’t pull it without pulling the cooling unit. Got on here and then buttoned everything back up when I couldn’t find the parts. Wonder if unplugging the amplifier reset something.
 
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Glad you got it working. Sounds like you probably had some corrosion on the terminals and the plugs were making bad contact. If it happens again I would start by cleaning the terminals on the AC amplifier and the connectors.
 
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so update on this situation. Medium settings stopped working again. Removed AC amplifier and cleaned contacts. Still not working. Ordered a used AC amplifier and put it in. Still not working. So unless both amplifiers were bad, doesn’t appear to be the amplifier.
 

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