A/C Clutch Shut Off

[XCRN]

In a stock configuration, does the AC clutch disengage at higher rpms or full throttle conditions?

I am adapting AC to my LS swap and since I am using the Jeep PCM to control my gauges where it still gets a VSS and Tach signal, I figured it would be a good way to control the AC to shut off at higher RPMs like how GM does it.

 

[Steel City 06]

It can be enabled via tune, but otherwise it will not shut off at high RPMs unless the low or high pressure switches kick it off

 

[KennethS]

You could install a switch somewhere on the throttle to open the circuit when the throttle is opened beyond some point.

 

[NskLJ]

In a stock configuration, does the AC clutch disengage at higher rpms or full throttle conditions?

I am adapting AC to my LS swap and since I am using the Jeep PCM to control my gauges where it still gets a VSS and Tach signal, I figured it would be a good way to control the AC to shut off at higher RPMs like how GM does it.

I have not wired any LS swaps but I do many ford motor swap. I would tire the A/c into the GM harness. This is how I do it on the Ford 5.0l swaps. There should be a A/c demand wire at the computer. Tie the wire from the Jeep a/c control to this wire. The high pressure switch may tie into the computer also. I would adapt a Gm switch to the factory Jeep line or and an inline adapter at the condenser for the switch and wire it in just like GM does it.

 

[SkylinesSuck]

It can be enabled via tune, but otherwise it will not shut off at high RPMs unless the low or high pressure switches kick it off

Via HP Tuners on a stock PCM?

 

[XCRN]

I have not wired any LS swaps but I do many ford motor swap. I would tire the A/c into the GM harness. This is how I do it on the Ford 5.0l swaps. There should be a A/c demand wire at the computer. Tie the wire from the Jeep a/c control to this wire. The high pressure switch may tie into the computer also. I would adapt a Gm switch to the factory Jeep line or and an inline adapter at the condenser for the switch and wire it in just like GM does it.

Gen 4 and 5 motors use the BCM to control the AC so that is unfortunately not an option.

 

[Rickyd]

Gen 4 and 5 motors use the BCM to control the AC so that is unfortunately not an option.

You don't think there are any rpm dependant outputs from the pcm you could use to trigger a relay on the ac clutch?

 

[NskLJ]

Gen 4 and 5 motors use the BCM to control the AC so that is unfortunately not an option.

The I would just wire the A/C as a stand alone system.

 

[XCRN]

You don't think there are any rpm dependant outputs from the pcm you could use to trigger a relay on the ac clutch?

Gen 3 engines do, gen 4 and 5 trucks and cars cycle the AC through the BCM. Thats why I was hoping the Jeep PCM cycled the AC clutch like Gen 3 trucks where its controlled through PCM and can shut the AC off depending on RPM which my Jeep PCM gets the tach signal.

 

[XCRN]

The I would just wire the A/C as a stand alone system.

How so? Like wiring a GM BCM to it somehow? I am basically using the Jeep PCM as BCM for the gauges and trying to figure out the cruise control as well. So if it can cycle the AC like a factory vehicle minus the idle increase which I doubt will be an issue with a V8.

 

[Rickyd]

Gen 3 engines do, gen 4 and 5 trucks and cars cycle the AC through the BCM. Thats why I was hoping the Jeep PCM cycled the AC clutch like Gen 3 trucks where its controlled through PCM and can shut the AC off depending on RPM which my Jeep PCM gets the tach signal.

Sorry i should have been more clear. If you just want to disengage the ac clutch at high rpms can't you program an output on the ls pcm to open a relay?

 

[NskLJ]

How so? Like wiring a GM BCM to it somehow? I am basically using the Jeep PCM as BCM for the gauges and trying to figure out the cruise control as well. So if it can cycle the AC like a factory vehicle minus the idle increase which I doubt will be an issue with a V8.

Wire it like the Jeep, the Gm idle control should compensate for the idle even though it doesn’t see the A/C on input. Are you running a mechanical fan or electric fans?
Here is how to make it stand alone connect the two wires together and tie the GM clutch wire into connector C103. If you are using and electric fan you could tie into the A/C on wire or the clutch wire to trigger another relay to turn on the electric or auxiliary fan.

 

[XCRN]

Wire it like the Jeep, the Gm idle control should compensate for the idle even though it doesn’t see the A/C on input. Are you running a mechanical fan or electric fans?
Here is how to make it stand alone connect the two wires together and tie the GM clutch wire into connector C103. If you are using and electric fan you could tie into the A/C on wire or the clutch wire to trigger another relay to turn on the electric or auxiliary fan.

That is my plan just not sure if the Jeep PCM would disengage the clutch at a certain RPM. I am on electric fans so its also a matter of figuring out how to have the fan turn on from coolant temp not turn on the AC compressor. I was thinking of using a diode on the AC request side so the ground signal goes to the fan relay signal wire but the fan request wont go to the AC relay signal. But 2 seperate relays is not a bad idea.

This diagram was before I was thinking of using Jeep PCM and was doing a very basic setup. But the AC shutoff at RPM is probably a good idea to prevent accidental damage to compressor.

 

[NskLJ]

If you tied the fan into pin 30 on the relay and attached battery to pin 87. Then you could tie in a A/c relay to feed power to when the A/C is on to pin 87a on the fan relay ( 5 pin relay) this would feed power when the cooling fan relay is off to the fan this would totally isolate the A/c from the GM pcm but still allow the cooling fan to work when needed?
Excuse my fingerpainting