Installing ac system in LS swapped FJ60 (3 Viewers)

[AggieOverlander]

Hey this question is for those that have put an LS engine in their rigs or general mechanics. The PO installed a LS engine but did not install the AC. So I know I need a Chevy compressor to fit the engine but from there is where I have my questions regarding equipment replacement. The PO left the dryer and all the hoses in a crate in the back of the rig and the condenser is installed in the front. I do not know the condition that the parts are in. So the three options I am looking at are:
Option 1 I use these old parts and use a converter fitting to fit the Toyota system to the Chevy compressor

Option 2 start fresh with a new Chevy compressor and new Toyota dryer, hoses and condenser and just mate the Chevy compressor using converter fittings to the rest of the new system

Option 3 start fresh with a new Chevy compressor, dryer, hoses and condenser and just mate that to the internal parts of the ac system with converter fittings.

Really haven’t priced things out yet just looking for ways the community would skin this cat. Also I live in Houston we going without ac is not an option. We have been over 100 for over a month now with no relief in sight.

 

[Dubs2017]

Depending on the condition I would replace everything that is available and flush the parts that aren't. Condenser might be tricky to find. Receiver drier is readily available, as is the evaporator. Most LS/Vortecs came with a Denso 10S17F compressor, which are easy to source. You can reuse a few of your hoses, and will need to reuse the curved discharge hose that connects to your condenser. I'd say start by grabbing a compressor and connecting your hoses that are in the crate. You'll definitely need some adapters for the compressor, but will still need to get new ends crimped onto the land cruiser lines. Can get them on ebay or amazon, or Mosley sells a kit and the adapters.

Do you know how the PO wired the pcm with the dash switch, or how the compressor power is wired?

On mine I skipped the stock AC amp and low pressure switch, and instead ran a separate binary switch on the high side.

Good luck!

 

[AggieOverlander]

Depending on the condition I would replace everything that is available and flush the parts that aren't. Condenser might be tricky to find. Receiver drier is readily available, as is the evaporator. Most LS/Vortecs came with a Denso 10S17F compressor, which are easy to source. You can reuse a few of your hoses, and will need to reuse the curved discharge hose that connects to your condenser. I'd say start by grabbing a compressor and connecting your hoses that are in the crate. You'll definitely need some adapters for the compressor, but will still need to get new ends crimped onto the land cruiser lines. Can get them on ebay or amazon, or Mosley sells a kit and the adapters.

Do you know how the PO wired the pcm with the dash switch, or how the compressor power is wired?

On mine I skipped the stock AC amp and low pressure switch, and instead ran a separate binary switch on the high side.

Good luck!

Thanks a ton for the advice!! I started sourcing parts last night. I knew about the Mosley kit and was going to use that. Regarding the PO wired the dash switch and compressor. The compressor was not installed so I am taking that as a sign that it was not wired into the PCM. Regarding wiring I am working my way through understanding how things so any articles or forum pages that can help educate me I appreciate. I am using the mud forum page by dbbowen on swapping an LS that been my go to article on this trip I am on.

 

[Dubs2017]

Thanks a ton for the advice!! I started sourcing parts last night. I knew about the Mosley kit and was going to use that. Regarding the PO wired the dash switch and compressor. The compressor was not installed so I am taking that as a sign that it was not wired into the PCM. Regarding wiring I am working my way through understanding how things so any articles or forum pages that can help educate me I appreciate. I am using the mud forum page by dbbowen on swapping an LS that been my go to article on this trip I am on.

Sounds like you’re off to a good start. What setup do you have? Gen 3 or 4, and e-fans or mechanical? And do you know where your harness is from? You could also grab a pin out of your pcm and see if you have continuity from your dash switch to the A/C Compressor Cycling Switch Signal (C2-55 on my gen iii). That would at least tell you if the PO connected that wire so that the pcm idles up. Also from your dash switch to your a/c compressor wire that is hopefully dangling in your engine bay.

 

[AggieOverlander]

Sounds like you’re off to a good start. What setup do you have? Gen 3 or 4, and e-fans or mechanical? And do you know where your harness is from? You could also grab a pin out of your pcm and see if you have continuity from your dash switch to the A/C Compressor Cycling Switch Signal (C2-55 on my gen iii). That would at least tell you if the PO connected that wire so that the pcm idles up. Also from your dash switch to your a/c compressor wire that is hopefully dangling in your engine bay.

I am pretty sure it is a Gen 3 as it was pulled out of a 2006 Silverado. I am not sure about the wiring. I understand the engine side of wiring as I had to replace on heads due to a broken bolt head on the header that was leaking. Right now I have been working on issues with the main harness and a short in the system. I am about to open up the dash and replace the main harness. I have a few LS swap websites and will start looking at for the PCM wiring and the internal wiring diagram. I do know the OBD II plug is inside the cab. I also want to swap out the choke light for a check engine light but one thing at a time. I got to get the main harness in and get the thing to start again.

 

[tmxmotorsports]

You don't need the computer to operate the ac system. Use the 62 ac compressor wire to trigger the ac clutch.

 

[tmxmotorsports]

You don't need the computer to operate the ac system. Use the 62 ac compressor wire to trigger the ac clutch.

Sorry I mean 60 look up ac Amp mod do that and use the 60 compressor trigger wire to trigger ac compressor use all the 60 oem parts replace them if you can. There is a 134a thermo coupler having brain fart I think that's what it's called and use Mosley motors ac line kit and your good to go.

 

[Dubs2017]

Sorry I mean 60 look up ac Amp mod do that and use the 60 compressor trigger wire to trigger ac compressor use all the 60 oem parts replace them if you can. There is a 134a thermo coupler having brain fart I think that's what it's called and use Mosley motors ac line kit and your good to go.

Yeah sorry @AggieOverlander I went down the LS pcm controlled AC route. Tommy is of course 100% right - you can totally just use the AC Amp Mod to trigger your compressor and bypass the LS PCM completely. This will give you a low pressure cut off switch (located next to the evaporator), but no high pressure cut off.

But, if you have e-fans, might be worth putting a trinary switch in (you can thread this into the plugged port on your new receiver/dryer) and using it to control your fans as well as easily incorporating a high/low pressure safety cut off. If you bypass the LC amp system, you can switch through the PCM and get your idle speed adjusted when AC is on, as well as AC off at WOT (if you're into that kinda thing). Totally depends on what you're going for in your rig.

Attached is the pcm pin out for Gen III, and here is a good resource for figuring out what you have. As you can see on page 2 of the attached, C2 (red) pin 55 is the compressor cycling switch wire that I mentioned above. And C2 - 43 is the AC Clutch Relay Control. This goes to ground when pin C2-55 gets 12v, so can be used as a switched ground for a relay that controls the compressor (assuming the tuner enabled this in your PCM).

Also, I just went through my entire dash wiring loom (albeit on a 62). Let me know if you have any questions. Happy to help since it is all front of mind still. I didn't post a ton about it, but here are a few pics.

Couple of other links worth reading:

Upgrading to Gen III LS-Series PCM: Air Conditioning Guide

Upgrading to Gen III LS-Series PCM: Air Conditioning Guide includes instructional photos, checklists, and step-by-step instructions on upgrading to the GM Gen III LS-Series PCM, ECM, Electronics, and POWERTRAIN CONTROL SYSTEMS

www.lsenginediy.com

Gen3 Air Conditioning

going over all info for utilizing the pcm to control a/c on a swap

www.lt1swap.com

Builds - 6.0 Vortec LQ9 - FJ60 Engine Swap - Old Blue's Heart Transplant

Nice. I’ll give em a look. These were a $4 purchase at Ace Hardware in the bolt aisle. (Where I spend my free time - haha) Plan on implementing a better system down the road. These are the “get the damn thing running version” yea check out those style of battery cable terminals.... you'll...

forum.ih8mud.com

 

[tmxmotorsports]

Also the gm computer will see a load and will idle up .

 

[AggieOverlander]

Thanks guys for all the help. You guys have definitely given me enough information to read study and plan how I am going to attack this monster. Also I will definitely reach out to you guys for help when I get to this step in my build.

 

[Richfj60]

Hi all, need to hijack this post.... I bought my 62 with a swap already done. I have the AC on/off switch wired directly to the AC clutch. The problem is that it freezes up and I have to manually turn it off and let it thaw out before it works again. I had to replace the evaporator box, evaporator and while I was at it the pressure switch and expansion valve, but it was never rewired. Fast forward a few years later and while I am doing some reassembly work after a paint job, I want to tackle the nuisance stuff. I've pulled the dash.

1. Can I utilize the pressure switch inside the evaporator? I have an 5.3 LQ9 out of a 2004 Silverado.
2. Does anyone have a wiring diagram of the system after the swap?
3. How is the on/off button, PCM, and pressure switch integrated?
4. Will this solve my problem?

I've seen some information about the IAC chip, frankly I don't understand that stuff, so need baby steps to help me. Maybe there is a post I haven't found yet. Any help is appreciated.

 

[Dubs2017]

Simplest way forward is to forgo the toyota low pressure switch near the evaporator as well as the gm pcm and just wire a binary switch to interrupt the ground of the ac compressor. There is a port on the side of the receiver/dryer that you can thread it into.

You’ve got power going to the compressor from your dash switch, so just cut the other wire coming from the compressor between the compressor and wherever you have it grounded and connect the two wires on the binary switch to either end. This way if the low or high limit are triggered it will cut the ground and shut the compressor off.

Here is a video about binary switches:


Freezing up is usually an expansion valve or moisture in the system as far as I know. I’m sure more knowledgeable folks will chime in.

Those links I posted above will give you wiring diagrams for the more complicated system if you want to incorporate the gm computer to gain things like idle up and shutting the compressor off while in WOT.

 

[Richfj60]

Simplest way forward is to forgo the toyota low pressure switch near the evaporator as well as the gm pcm and just wire a binary switch to interrupt the ground of the ac compressor. There is a port on the side of the receiver/dryer that you can thread it into.

You’ve got power going to the compressor from your dash switch, so just cut the other wire coming from the compressor between the compressor and wherever you have it grounded and connect the two wires on the binary switch to either end. This way if the low or high limit are triggered it will cut the ground and shut the compressor off.

Here is a video about binary switches:


Freezing up is usually an expansion valve or moisture in the system as far as I know. I’m sure more knowledgeable folks will chime in.

Those links I posted above will give you wiring diagrams for the more complicated system if you want to incorporate the gm computer to gain things like idle up and shutting the compressor off while in WOT.

Thank you so much!! Great video and follow up video on wiring up the switch. Pretty simple. As for the Idle up, I'll have to check if my ECM supports. Not sure what WOT is. I appreciate all that you have posted. The video was the baby step I needed, now I understand it a little better. Definitely need the binary switch. Don't have electric fans, the so Trianary doesn't apply. I was afraid I'd have a phD by the time this is over.

 

[Dubs2017]

Haha I know what you mean. It finally clicked for me at one point, too. Happy to help.

WOT is “wide open throttle.” Essentially if you floor it with the ac on the computer will turn the compressor off so that you have maximum power.