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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
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Toyota pickup: Im doing a/c work on a 1993 TOYOTA P/UP 4 CYL

Customer Question

Im doing a/c work on a 1993 TOYOTA P/UP 4 CYL 22RE . I CHNGED THE DRYER, CONDENSOR, COMPRESSOR, CUT OFF SWITCH AND EXPANSION VALVE. MY PROBLEM IS WHEN I TRY TO CHARGE THE SYSTEM AFTER EVACTING THE SYSTEM, THE COMPRESSOR ENGAGE TO LOW PRESSURE RAISE TO 90 LBS AND THE HIGH SIDE GOES TO 125 LBS THAN THE COMPRESSOR CUTS OUT AND COMES BACK ON AND CUTS OFF AND ON TILL THE PRESSURE IS 90 LBS AND THE HIGH AT 150. AND COMPRESSOR DONT COME ON AT ALL. wHAT COULD BE MY PROBLEM?
Submitted: 1 year ago.
Category: Toyota
Expert:  Toyota Service replied 1 year ago.
Hello. Welcome to Just Answer. Please allow me to assist you. This sounds very much like your replacement expansion valve is sticking. If this vehicle was in my shop, I would be pulling the evaporator back out and replacing the expansion valve. You might want to check the evaporator too. If somebody put AC stop leak in the system, the evaopratopr may be plugged up (which would mimic a bad expansion valve and give you the bizarre pressures you see on your gauges. If you have any questions, please feel free to reply.Thanks for choosing Just Answer. It was a pleasure to assist you today. I trust my input to your request is satisfactory to you and meets your expectations. A positive rating would be greatly appreciated for my assistance on your inquiry. Thanks in advance and thank you again for choosing Just Answer
Customer: replied 1 year ago.
change the extention valve again and same results. If I jump from batt to compressor wire compressor stays on, got the pressure to 40 on low and 200 on high, turn engine off the pressure drops to 95 low and 100 high. start engine and compressor don't come on. im lost
Expert:  Toyota Service replied 1 year ago.
Does the ac relay click when you turn on the ac switch? The relay might be labeled MG CL in the fuse panel under the hood.
Customer: replied 1 year ago.
yes a relay on top off the valve cover going to the idle knob clicks.
Expert:  Toyota Service replied 1 year ago.
That is the idle up solenoid. You need to find the AC relay. In the fuse box.
Customer: replied 1 year ago.
I found a relay under the dash with a 6n29 number. Is this it if so it doesn't click when turning the ac switch on and off. This relay is on the rightside under dash .
Customer: replied 1 year ago.
There is a 30 amp and 10 amp fusses and there is a lable that reads ac and heather.
Expert:  Toyota Service replied 1 year ago.
Is the ac relay getting power?
Customer: replied 1 year ago.
yes but relay no clicking. Is it a bad relay?
Customer: replied 1 year ago.
called the parts store and they said that's the blower relay, the ac relay is under the hood and its a round 4 pong but I cant find it
Expert:  Toyota Service replied 1 year ago.
Ok. I need to grab my wiring book on this. I'm can't get to it for 2 1/2 hours, as I am driving home. I will reply as soon as I get it.
Expert:  Toyota Service replied 1 year ago.
Ok.
1) Does the AC switch light up? If not, check the 10 amp AC fuse nect to the heater relay under the dash on the right side.
2) The AC relay is in that same area. It is a 4 prong relay. the wire colors are as follows:
Contact side power in: Red/Green
Coil Side power in: Black/Yellow
Contact side power out (coil energized) Green (this goes to the AC Amplifier)
Coil side Ground circuit: Red
With the key on and the AC switch depressed, you should have power in the Blue/White wire on the AC amplifier.
If the relay is working correctly, you should have power at the Green wire at the AC amplifier.
If you do not have power on the Red/Green wire on the AC relay, your AC dual pressure switch is bad, disconnected or the pressure is too high or too low. The AC Dual Pressure Switch is on the freon line. It has a Black/Yellow wire and a Red/Green wire.
The AC Idle up solenoid clicks because it is controlled by the EFI computer, it is not part of the AC system
Power leave the AC amplifier to the compressor via the Black/White wire.
Pleaselook into all of the above and let me know what you find. Sorry for the delay; you caught me out of town.
Customer: replied 1 year ago.
The ac amplifier has the following color wires, 2 yellow/green, black, black/white, red/green, blue/white, white/black, and white/red. With everything plugged in (key in the on position, and ac button on) only the black, red/green, and blue/white wires have power.
Customer: replied 1 year ago.
Also could not locate 4 prong relay
Expert:  Toyota Service replied 1 year ago.
4 or 6 cylinder?
Expert:  Toyota Service replied 1 year ago.
I'm guessing that you do not have a 4WD automatic V6 here. If so, you do not have an AC relay
Expert:  Toyota Service replied 1 year ago.
The switch powers the Blue White wire.
Expert:  Toyota Service replied 1 year ago.
The AC Fuse powers the wire to the AC dual pressure switch (the Black/Yellow wire on the switch)
Expert:  Toyota Service replied 1 year ago.
the Dual pressure switch, if satisfied by freon pressure, allows power to flow the AC amp via the Red/green wire.
Customer: replied 1 year ago.
4wd manual 4 cylinder
Expert:  Toyota Service replied 1 year ago.
The two yellow green wires are from the temperature probe/thermister. This tells the amplifier tha the cabin is warm and turns on the compressor and shuts it off when the evaporator temperature is around 34 degrees
Expert:  Toyota Service replied 1 year ago.
The black wire comes form the ignition coil/igniter
Expert:  Toyota Service replied 1 year ago.
The black/white wire powers the compressor clutch
Expert:  Toyota Service replied 1 year ago.
White red is a signal from the EFI computer
Expert:  Toyota Service replied 1 year ago.
So, when properly operating, you should have power in the blue/white wire; engine running, AC switch on.
Expert:  Toyota Service replied 1 year ago.
You should have power in the Red/Green wire if the AC dual pressure switch is satisfied with system pressure
Expert:  Toyota Service replied 1 year ago.
The power to the compressor is the Black/White wire and the system ground is the White/Black wire.

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