Deciphering PO’s A/C Wiring (1 Viewer)

dogcruiser

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Thanks Jim. I figured that’s what this was for, in one way or another. Knowing where to turn the knob is a wild guess to me. I’m guessing there some resistance value that equates to the correct temperature.

Jim I misread your post. You’re saying run the AC and check the vent temp, adjusting the knob until the temp is just above 40. Makes sense
 
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I have exactly the same set up in my 83 FJ60. My rig was bought in Wyoming about 8 years ago. The AC never worked. The AC button I installed. The "original" works with the blue toggle switch that still has power to it but I have no idea where the clutch control wires are as the entire unit was stipped to the bone and then reassembled. I didn't know at the time that the AC was nonfunctional or that is had aftermarket set up so now I have 5.3L vortec with GM compressor but no idea where the clutch control wires are. I assume they would be the secondary off the relay and the relay controlled by the thermostat. Will need to get in there with a multimeter to try to sort it out. From the above I am assuming there is no AC amplifier. The AC button you see was put in by me thinking I needed this to control AC before I realized that this was not standard system.
Do you suppose this set up has a low pressure switch in the circuit?

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Here is what I figured out so far. I'm not convinced my toggle switch is hooked up correctly. The indicator light come on-off and the Red gets power when indicator light is off. My thermostat only has one wire connected to it and the Wb, Bk, and RBk wires from the plug disappear into the original wiring harness.
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@FJ60 guy see the attached PDF of the wiring diagram. It’s the factory setup but it may help

Regrettably knowing the factory set up doesn't help much since these units don't have the factory set up. There is apparently no AC amplifier and as I haven't taken the evaporator apart yet I don't know if it has a thermistor and or low pressure valve incorporated. But thanks anyway.
 
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San Diego, CA
Here is what I figured out so far. I'm not convinced my toggle switch is hooked up correctly. The indicator light come on-off and the Red gets power when indicator light is off. My thermostat only has one wire connected to it and the Wb, Bk, and RBk wires from the plug disappear into the original wiring harness.

Why not just let the GM ECU control the AC? You can just provide a +12v to the request line, add in a relay (ECU grounds the relay to trigger the clutch) and wire in the safety switches to the ECU/request circuit. With the state of your existing setup this may be the easier way to go.

I ended up going down this path even though I have factory A/C and the A/C Amp (the amp clutch enable triggers the GM ECU A/C request and has the low pressure switch as part of its circuit, GM ECU gets the control request and uses the high pressure switch on the compressor as the low pressure safety input into the ECU and triggers the a/c relay which goes to the compressor clutch engage) to get factory like idle compensation, high and low safety switches and system error handling.

What Motor/ECU are you running? Here is a great page on how the Gen3 stuff works Upgrading to Gen III LS-Series PCM: Air Conditioning Guide
 
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Why not just let the GM ECU control the AC? You can just provide a +12v to the request line, add in a relay (ECU grounds the relay to trigger the clutch) and wire in the safety switches to the ECU/request circuit. With the state of your existing setup this may be the easier way to go.

I ended up going down this path even though I have factory A/C and the A/C Amp (the amp clutch enable triggers the GM ECU A/C request and has the low pressure switch as part of its circuit, GM ECU gets the control request and uses the high pressure switch on the compressor as the low pressure safety input into the ECU and triggers the a/c relay which goes to the compressor clutch engage) to get factory like idle compensation, high and low safety switches and system error handling.

What Motor/ECU are you running? Here is a great page on how the Gen3 stuff works Upgrading to Gen III LS-Series PCM: Air Conditioning Guide

You're probably right. I had seen the article you linked to before but as I thought I had a normal system my thought was to do what you did and use the AC amp output to the ECU or even direct to the clutch but then I found out I don't have an AC amp and as I haven't dismantled the condenser housing yet don't know if I have a low pressure switch and thermister so was looking for alternatives, but the ECU route is probably best. I have room for an extra relay in my relay box and would have to see how to install a low pressure switch and anti freeze up thermister. Not sure if my compressor has a built in high pressure switch but will check. If nothing else probably had a port for one. I have a 2007 5.3L vortec from an Avalanche truck. I need to confirm this.... but if so it uses a serial data link to an AC control module slightly complicating things. So I have a small list of things to verify first it seems.
 
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You're probably right. I had seen the article you linked to before but as I thought I had a normal system my thought was to do what you did and use the AC amp output to the ECU or even direct to the clutch but then I found out I don't have an AC amp and as I haven't dismantled the condenser housing yet don't know if I have a low pressure switch and thermister so was looking for alternatives, but the ECU route is probably best. I have room for an extra relay in my relay box and would have to see how to install a low pressure switch and anti freeze up thermister. Not sure if my compressor has a built in high pressure switch but will check. If nothing else probably had a port for one. I have a 2007 5.3L vortec from an Avalanche truck. I need to confirm this.... but if so it uses a serial data link to an AC control module slightly complicating things. So I have a small list of things to verify first it seems.

Ah, yeah the Gen4 stuff probably complicates things a bunch, my setup is from a 2000 Suburban 1500 so pretty straight forward and the safety switches are just open or closed circuits, not actual pressure values on the later systems. Hopefully you can just drop in the A/C module and appropriate sensors and still get the 12v trigger and let ECU control the rest solution. Good Luck!
 
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To complicate things further I find my unit is apparently some older design evaporator. The expansion valve is in the engine compartment and there is no provision for a low pressure sensor, thermistor or the larger evaporator now used. So going to look for a complete evaporator system housing and all and hope it mates up with the rest of the system.

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cruisermatt

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To complicate things further I find my unit is apparently some older design evaporator. The expansion valve is in the engine compartment and there is no provision for a low pressure sensor, thermistor or the larger evaporator now used. So going to look for a complete evaporator system housing and all and hope it mates up with the rest of the system.

Yes, if you read back in this thread, your 60 had a complete aftermarket system. A complete Toyota evaporator core and housing will fit right in and contains the expansion valve inside it. I had to drill new holes in the firewall for the lines to exit in the correct location. The grommets for those lines are still available new from Toyota and were about $3.50 each.

and then you can buy the very nice Mosely Motors LS swap AC hose kit from @FJ60Cam and you’ll be good to go.

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Yes, if you read back in this thread, your 60 had a complete aftermarket system. A complete Toyota evaporator core and housing will fit right in and contains the expansion valve inside it. I had to drill new holes in the firewall for the lines to exit in the correct location. The grommets for those lines are still available new from Toyota and were about $3.50 each.

and then you can buy the very nice Mosely Motors LS swap AC hose kit from @FJ60Cam and you’ll be good to go.

View attachment 2521784
Do you have part number for that core? In a separate thread a guy with my same set up got the denso FJ 60 core and found it to be about 3" too tall to fit in his housing.
 

cruisermatt

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Do you have part number for that core? In a separate thread a guy with my same set up got the denso FJ 60 core and found it to be about 3" too tall to fit in his housing.

All 60’s with factory AC have the same evaporator core. I saw that thread. He was trying to use a OEM style evaporator in the aftermarket housing which is half the size. I posted a picture comparing the two earlier in this thread.
 

cruisermatt

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So l just need to find a new housing. With sensor pipe and core.....

Yep, new cores are only about $80 for a Denso on Rock Auto or Parts Geek so worth doing. New expansion valves are cheap as well. There's about 8" of aluminum piping that you need that goes from the expansion valve through the firewall that you can't get new so make sure you get that with the housing.
 

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