1980 Fj40 Factory Nippondenso A/C Tech Question..Please Help!! (1 Viewer)

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I bought 1980 Fj40 with the factory NipponDenso a/c. Here is the problem: When turning on the a/c by the control in the cab, the compressor will not turn on. The controls all seem to work including the fan, but the controls will not engage the compressor. I did get the compressor to work by doing an override at the the pressure switch. I also got it to work by doing an override at the electrical connection at the interior on/off control. When doing this, everthing works fine and the a/c blows COLD! I think the problem has something to do with the fact that this fj was de-smogged by one of the previous owners. I am wondering if they removed a part out of the a/c circuit that would engage the compressor when turned on. From the wiring diagrams i have seen on line, it seems like there is suppose to be a A/C solenoid/or some sort of idle up solenoid that is part of the a/c system. I am thinking my fj may be either missing this or its not hooked up. Here are some pictures of where I think the problem my be. There are several electrial contections here that are not hooked up and I think one of these is the problem..BUT not really sure?? I dont want to put all the smog stuff back on, but rather just ad the piece that is needed to get the air to work. Thanks in advance for your help!!
photo 2[1].JPG
photo 1.JPG
 

FJ40Jim

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The AC is controlled by a computer box that Toyota euphemistically calls an "AC Amplifier".
The AC amp has inputs: fan, pressure switch, temp sensor, tach.
Outputs are: compressor, AC idle up.

If any of the inputs/outputs are wrong, the system will not work. So if the coil isn't connected to tach wire or the AC idle up VSV isn't plugged in, then AC will not work.
 
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The AC is controlled by a computer box that Toyota euphemistically calls an "AC Amplifier".
The AC amp has inputs: fan, pressure switch, temp sensor, tach.
Outputs are: compressor, AC idle up.

If any of the inputs/outputs are wrong, the system will not work. So if the coil isn't connected to tach wire or the AC idle up VSV isn't plugged in, then AC will not work.
Thanks for the info. I did not think the 1980 had the a/c amplifier on it so I will have to check this out! Thanks!
 

bj40green

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Just for explanation purposes... This is a diagram for a BJ FJ HJ 60 series A/C system.
As you can see, everything is hooked up to the Amplifier.
This is basically how it works.
AC BJ FJ HJ 60 series.JPG


Sorry, have no service manual for a 40 series.

Rudi
 
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Just for explanation purposes... This is a diagram for a BJ FJ HJ 60 series A/C system.
As you can see, everything is hooked up to the Amplifier.
This is basically how it works.
View attachment 936890

Sorry, have no service manual for a 40 series.

Rudi
Thanks a ton! My Manuel does not have this diagram. I will start tracking down what I'm missing...
 
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Let me know if you need one. I happen to have one in my personal stash.
I guess I don't even know if I need one or not. Where is it usually located and what's it look like? I seemed to be able to fix about anything mechanical but electrical issues drive me nuts! Thanks !!
 
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It doesn't say if it's a hi or low pressure switch, but if you had to jumper it I would put gauges on it and check suction and discharge pressures. Or maybe the pressure switch is screwed... If it blows really cold you have lost some refrigerant, which would explain why jumper in the pressure switch makes it run.
 

bj40green

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I guess I don't even know if I need one or not. Where is it usually located and what's it look like? I seemed to be able to fix about anything mechanical but electrical issues drive me nuts! Thanks !!

The Amplifier (full name A/C idle Amplifier) is the control box that allows the compressor to run when all conditions are met. So if you can get it to work by a jumer or an override it means that the magic Amplifier box is there.
The fact that it doesn't work means that one or more conditions are not valid.
The diagram I posted is for basic understanding of how it works. In reality there are much more components involved (not shown in this diagram) which can cause the problem.

Do what Cruiserdnerd suggested; check the pressure or go to a specialized A/C shop. A pressure test takes only a few minutes and they can tell you what's wrong with it.

Rudi

PS, when I look up the control unit 88610-60050 and look at the price I think that the Amplifier is inside that control panel. See this: http://picclick.com/COOLER-CONTROL-SWITCH-LAND-CRUISER-FJ40-FJ43-FJ45-171355727620.html or this one: http://www.toyodiy.com/parts/p_E_198402_TOYOTA_LAND+CRUISER_FJ40LV-MC_8714.html
That's a lot of money for a box with a speed selector and a temperature selector.
 
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The Amplifier (full name A/C idle Amplifier) is the control box that allows the compressor to run when all conditions are met. So if you can get it to work by a jumer or an override it means that the magic Amplifier box is there.
The fact that it doesn't work means that one or more conditions are not valid.
The diagram I posted is for basic understanding of how it works. In reality there are much more components involved (not shown in this diagram) which can cause the problem.

Do what Cruiserdnerd suggested; check the pressure or go to a specialized A/C shop. A pressure test takes only a few minutes and they can tell you what's wrong with it.

Rudi

PS, when I look up the control unit 88610-60050 and look at the price I think that the Amplifier is inside that control panel. See this: http://picclick.com/COOLER-CONTROL-SWITCH-LAND-CRUISER-FJ40-FJ43-FJ45-171355727620.html or this one: http://www.toyodiy.com/parts/p_E_198402_TOYOTA_LAND CRUISER_FJ40LV-MC_8714.html
That's a lot of money for a box with a speed selector and a temperature selector.


Thats crazy money for that thing....I did have the pressure checked and my a/c guy said it was within the specs. Not sure what that was. It seems correct that the issue lies within the a/c amplifier circuit. I know there are things that are disconnected so it must not be receiving the signals it needs to allow the compressor to kick on. Like I said earlier, we got it to function by overriding it at the pressure switch and at the wiring harness for the on/off/temp controller, but no where else. From some of the other threads people say you can jumper the wires at the controller to make it work, but thats not my idea of fixing it...
 

bj40green

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fjc-man

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ok if somebody has chassis manual 98154 (1980 FJ40?) or chassis supplement RM98344 and wouldn't mind seeing which includes a wiring diagram of the optional oem nippondenso a/c system we could keep this diagnosis going.....
 
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Thanks again for the research. I noticed the supplement only seemed to deal with the power steering. I did fun a a/c Manuel for a 1980 fj55. Not sure how close the wiring is for a 40 but the customer service guy said it should be very close as they both used the same unit...?? Not sure about that info but I ordered it and will find out this week.
 

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