Jeep factory A/C rewiring for diesel engine - Pirate4x4.Com : 4x4 and Off-Road Forum

carcrafter22 · 08-06-2012, 07:02 PM

Hi guys,

I'm finishing up the install of an isuzu diesel into my 2001 grand cherokee. After fighting many of the common jeep issues such as the failing pcm, wiring harness issues, instrument panels failing, and many more I have decided to just remove the factory pcm and engine harness and just run my own gauges.

The problem with no factory pcm is the factory electric fan won't kick on and the factory a/c won't cycle the air compressor, I'm still not sure how the temp control will work since I can't even get the compressor to cycle to charge the system.

Can anyone help with this?

The factory electric fan is simple, just a relay and temp switch with handle that. My big worry is making the factory a/c system work. Any ideas?

Thanks

Whitetrash303 · 08-07-2012, 11:20 PM

You can make the A/C work with the factory or aftermarket switch and a relay. Just make sure you wire it through the A/C pressure switch so the compressor doesn't run when the charge is too low or pressure is too high.

You can also use a diode and wire the same signal to your fan relay. That way the fan will run any time the A/C is on, but the A/C won't run just because the fan is on.

carcrafter22 · 08-08-2012, 10:23 AM

I removed the factory controls this morning and looked around for a minute. It looks like the vents are selected using vacuum tubes so that's not a problem. The blower speeds work fine as is. I just need to check the operation of the temp knob and see if I can wire it directly to the hi pressure switch.

Do you think it would be easier to install an aftermarket trinary switch that does high and low as well as kick on the fan when needed? I'm leaning that way right now.

08-06-2012, 07:02 PM	#1 (permalink)
carcrafter22 Registered User Join Date: Jun 2008 Member # 115135 Location: Burleson, Tx Posts: 95	Jeep factory A/C rewiring for diesel engine Hi guys, I'm finishing up the install of an isuzu diesel into my 2001 grand cherokee. After fighting many of the common jeep issues such as the failing pcm, wiring harness issues, instrument panels failing, and many more I have decided to just remove the factory pcm and engine harness and just run my own gauges. The problem with no factory pcm is the factory electric fan won't kick on and the factory a/c won't cycle the air compressor, I'm still not sure how the temp control will work since I can't even get the compressor to cycle to charge the system. Can anyone help with this? The factory electric fan is simple, just a relay and temp switch with handle that. My big worry is making the factory a/c system work. Any ideas? Thanks

08-07-2012, 11:20 PM	#2 (permalink)
Whitetrash303 Hardcore Web Wheeler Join Date: Nov 2007 Member # 102426 Location: Denver Posts: 992	You can make the A/C work with the factory or aftermarket switch and a relay. Just make sure you wire it through the A/C pressure switch so the compressor doesn't run when the charge is too low or pressure is too high. You can also use a diode and wire the same signal to your fan relay. That way the fan will run any time the A/C is on, but the A/C won't run just because the fan is on. __________________ The Answer to 1984 is 1776

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08-08-2012, 10:23 AM	#3 (permalink)
carcrafter22 Registered User Join Date: Jun 2008 Member # 115135 Location: Burleson, Tx Posts: 95	I removed the factory controls this morning and looked around for a minute. It looks like the vents are selected using vacuum tubes so that's not a problem. The blower speeds work fine as is. I just need to check the operation of the temp knob and see if I can wire it directly to the hi pressure switch. Do you think it would be easier to install an aftermarket trinary switch that does high and low as well as kick on the fan when needed? I'm leaning that way right now.