The A/C Amp Thread (3 Viewers)

[BigHighBlue]

@BigHighBlue

Contact @Engineer8000 He can fix your A/C Amp board (Service he offers) and has the components to do so.

Emissions Computer 89550-60130

I spent some time in the shop reverse engineering this module and drew up the schematics for the different functions. It has two proprietary ICs on it, one that handles RPM and one that handles the speed sensor and temperature sensor. These turn various transistors on and off to perform the...

forum.ih8mud.com

Thank you! He's already reached out to me. I very much appreciate the referral.

 

[Spike Strip]

As soon as summer is over, I'm going to remove mine and send it to him, also...

 

[BigHighBlue]

As soon as summer is over, I'm going to remove mine and send it to him, also...

Thats a great advertisement for @Engineer8000. Its hot as blazes here right now, I don't even want to drive my truck without A/C. I hoped recharging the system was going to be a quick fix, should have know better...

 

[84Landie]

Hi all,

I've got an '84 FJ60 w/ Sniper EFI. I removed the resistor on my AC amp as described in this thread, but now I'm hearing a high pitch electronic whine that seems to come and go as the AC amp kicks on and off. I don't hear it 100% of the time, but the noise is only present with AC on (comes and goes with the AC button on and off). It also seems like pitch is impacted by the engine RPM. Sounds kind of like a poorly grounded radio (I've checked that already).

Is this a sign my amplifier is going bad? Has anyone else experienced this?

 

[landcrusher909]

I found an old thread explained "
feed tach signal to the wire that attached to the negative side of the coil (stock I-6 coil) out under the hood.

Use stock toyota I-6 wire that connected to OEM compressor to signal a relay to energize GM compressor on GM V-8.

In dash controls work at that point once system is charged with freon. " I am working on the same thing right now with a 1985 FJ60 5.3 chevy conversion. I am trying to located the Tach signal they used to set up. Thanks for any help Rob

 

[FJ60Cam]

I found an old thread explained "
feed tach signal to the wire that attached to the negative side of the coil (stock I-6 coil) out under the hood.

Use stock toyota I-6 wire that connected to OEM compressor to signal a relay to energize GM compressor on GM V-8.

In dash controls work at that point once system is charged with freon. " I am working on the same thing right now with a 1985 FJ60 5.3 chevy conversion. I am trying to located the Tach signal they used to set up. Thanks for any help Rob

Are you looking for the tach signal to make the AC work or to make a tach work?

If you remove the resistor, you no longer need a tach signal to make the AC work.

 

[landcrusher909]

Yes I just want the AC to workI dont care about the tach signal. Which resistor do you mean ? Thanks for all the help.

 

[84Landie]

Check out post #4 of this thread.

 

[landcrusher909]

Check out post #4 of this thread.

THANKS ! After reading it a few times it finally clicked LOL

 

[84Landie]

THANKS ! After reading it a few times it finally clicked LOL

No problem! I did it earlier this year and must have read and re-read this thread half a dozen times before I actually moved forward. Did not want to remove the wrong one!

 

[landcrusher909]

I just want to say Thank you. I I removed the diode and everything is working Great. For you guys putting in the time and effort figuring out all this stuff and sharing it. If we ever meet up on the trail I've got a handshake and a beer waiting.

 

[TrickyT]

I just want to say Thank you. I I removed the diode and everything is working Great. For you guys putting in the time and effort figuring out all this stuff and sharing it. If we ever meet up on the trail I've got a handshake and a beer waiting.

It's a deal!

 

[Elbert]

landcrusher....glad you found help....the "high tech" tip about removing the resistor was unknown to me at the time of my experiment.

 

[turnrob]

This is an awesome thread with great information, wanted to thank everyone whose contributed. I have a FJ62 w/ 5.3 vortec thats been cleanly swapped and wired by previous owner without AC. I finished all the plumbing with custom hoses and a dirty dingo low AC mount. My last hurdle is this wiring. My plan was to use a trinary switch off my dakota digital fan controller, stock AC sender and the compressor.

I tried to locate the AC sender in the engine bay harness and its neatly wrapped and organized. Short of pulling the harness apart, id like to run a new relay off the AC amp box. My ac light is receiving power and my question is which wire would I run the new relay off? There's a larger white/black guage wire off the amp box but I don't think that's the one. Do I use the compressor clutch wire #7 in the chart? I've added some photos , photo 1 is the ac amp box.



Thank you!

 

[TrickyT]

With the new wiring for the vortec done by the previous owner, there's too many potential variables to provide definitive answers to your questions. Sorry. Best thing is to look at the wiring diagram in post #3 and wire the new A/C up based on that. There's no real need for a new relay if you make proper use of the existing A/C amp. As far as the wiring for the "AC sender" (I'm assuming you mean the pressure switch), you could just run a new wire and not mess with the wiring harness.

 

[FJoemike]

Maybe you guys answered this question already will the fj60 amplifier work in a fj62? Mines is missing

 

[fruitjack]

Maybe you guys answered this question already will the fj60 amplifier work in a fj62? Mines is missing

sadly no

 

[dbbowen]

This is an awesome thread with great information, wanted to thank everyone whose contributed. I have a FJ62 w/ 5.3 vortec thats been cleanly swapped and wired by previous owner without AC. I finished all the plumbing with custom hoses and a dirty dingo low AC mount. My last hurdle is this wiring. My plan was to use a trinary switch off my dakota digital fan controller, stock AC sender and the compressor.

I tried to locate the AC sender in the engine bay harness and its neatly wrapped and organized. Short of pulling the harness apart, id like to run a new relay off the AC amp box. My ac light is receiving power and my question is which wire would I run the new relay off? There's a larger white/black guage wire off the amp box but I don't think that's the one. Do I use the compressor clutch wire #7 in the chart? I've added some photos , photo 1 is the ac amp box.



Thank you!

I dont know if youve finished this yet, but if you have a gen3 motor and are running the stock pcm instead of like a holley terminator, you can just control it with the GM computer

 

[Eurasiaoverland]

For the EE’s out there, here are the schematics that I reverse engineered for the two boards.

View attachment 1070611

Both boards use a proprietary IC for the controller. On the FJ62 it’s a Toshiba T2333 and on the FJ60 it’s a Nippon Denso SE012. I could not find data sheets for either.

Firstly, thanks for the information on this thread, I have dipped into it now and then over the last couple of years and really aprpeciate your sharing!

I would like to share something potentially interesting, and ask a couple of questions.

I have a 1989 BJ60. This model is the last of the BJ60 production run and was only sold, as far as I know, in SE Asia. Given the climate here, the model came with no heater and optional A/C. My example did not come with factory A/C but has all the wiring in place. I have acquired the small A/C harness (cowl harness to evaporator box) from both a local BJ60 with factory A/C and an Australian vehicle with factory heating and A/C.

I am doing a restoration on the car and, as I intend to export it to Europe at some point, I am fitting factory heating and A/C, the components of which I have sourced used where necessary. I will use what you call the FJ62 board (077300-0841 / 88650-90A03) which is correct for my vehicle from factory.

Because it lacked a heater, the HVAC controls look like this (comparing with a 87+ Australian heater control - note my car is right-handed). You can see that the heat/cool slider becomes just a cooling slider, and that the far left shows 'OFF', something different from the heater/cooler version where only the A/C button can switch off the A/C.

Here is the heater control slider unit for comparison. The units are identical except that the heat/cool slider arm on the no-heater variant (left) has no cables attached, just a variable resistor (the control units are upside down here).

Here is that variable resistor:

The wires on the variable resistor are:
Yellow/black, which runs to Terminal 8 on your diagram of the board.
White/blue which runs to both Terminal 9 on the board and also runs (as two white/blue wires) to one of the terminals of the thermistor which is inside the evaporator box.

Could you shed any light on how this arrangement works? What signal is it modulating through the variable resistors?

It may seem a bit pointless to have a variable cut-off on the A/C, but in a tropical climate it is nice to have the A/C on low, e.g. on a rainy night when you want to keep the cabin dry but don't really need strong cooling. I'm thinking of trying to keep it, even though it is not really compatible with the heater arm on the heat/cool version of the heater sliders.

If I just took it out, would I need to jump the terminals where the variable resistior normally conenects to make a circuit?

The vehicle is totally dismantled so I cannot test if the system runs, though the entire vehicle wiring is out on my living room table/floor so I can test any circuit easily with a meter.

In writing this post I notice that the small AC wiring harness is different between an Australian version with heater and A/C, and this tropical version with cooling only. I'll write a separate post.

Thanks

EO

 

[Richfj60]

Trying to get the AC sorted on my 88 FJ62. I am knee deep in my dash and have some questions. After a lot of study I have a plan, but still some questions. If you look at my notes (see pictures below), the current set up bypasses the AC Amp, by wiring the AC switch directly to the AC clutch. It currently does not have the thermistor or pressure switch active. The proposed set up is to wire the output of the AC Amp directly to the AC clutch (original set up on a FJ62 goes through the ECU). Then add a high pressure switch to the ground side of the GM Compressor. That much is straightforward, but is it correct? Also, the Ignition wire to the AC Amp (the Black/white wire) is missing. While cleaning up the harness, I found an "unused" (post swap) Black/white 10Ga wire. Can I use that one?