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Unread 12-12-2011, 12:37 PM   #46
youngjeeper11
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That makes sense, however I am really doubting I will be able to fit a condensor anywhere in the grill, because I have an intercooler between my radiator and grill, where the YJ condensor would go.

I kind of like the idea of keeping my AC cooling and engine cooling completely seperate as well.

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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-12-2011, 01:19 PM   #47
Bojeepus
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i cant wait to see the finished system
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Unread 12-13-2011, 06:26 AM   #48
dodger889
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The A/C you will feel it on the diesel engine but in it's design it will recover from the load being applied. If you let the clutch out slowly at idle a diesel engine will compensate for that load. Also you have to remember that you are dealing with inertia weight that will absorb the load too.
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A 89 yj with a 4.0 aw4 sye out of an 92xj. Now the hard part is done time to get it up in the air just a bit. Working on 8.8 with 3.73 and lsd for the rear. and new D30 hp with 3.73 .
For those who have not figured this out I'm old school but can handle the new too.
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im just cheap, and cheap makes you creative.
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Unread 12-18-2011, 07:23 PM   #49
youngjeeper11
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alright heres where I am at after studying diagrams for like 6 hours

I ended up buying diagrams from alldatadiy.com, they are actually pretty decent.

The YJ and XJ systems are wired a little different. There is one difference I have not quite figured out. The XJ system has 1 extra wire that is supposed to go to one side of the low pressure switch, and it is totally absent in the YJ system, so I may need to run an extra wire. Also, the connector for the blower motor is under the hood in the engine bay in the XJ, and under the dash in the YJ, So I am going to have to run an extra wire for power to the motor out to the enigne bay as well.


in the pics you can see how there is 1 plug that connects the whole XJ HVAC wiring to the main harness, and the YJ system has 1 plug that connects just the AC system to the main harness, not the heating system.

So basically I cut the YJ plug off, and soldered the XJ connector on in its place after I figured out what wires were similar.

My only mystery right now is there there was a red and black wire on the YJ connector that was some how for a cigar lighter, is there a cigar lighter mounted on the YJ AC system?

In reality, it is only 5 wires to get it to work.

Also, during my research, I found that the blower motor resistor in the XJ system is known for going bad, so I may replace that off the bat. I need to flush the heater core as well.

I wish I could have mounted the unit this weekend, but my saw-z-all I ordered is about a week late..... USPS sucks....
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-19-2011, 07:29 AM   #50
Que89YJ
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The blower resistor pack is a high fail on YJ, XJ, .....all of the vehicles that use them. If you have a working block just make sure it's accessible it your new config.

It's looking good. I am just finding it hard to appreciate a good ac right now here when it's 20 at night outside! LOL
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Unread 12-19-2011, 09:48 AM   #51
youngjeeper11
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Yea, it should be easy to replace.

Its not much better here in VA, but I figure it will be warm by the time I actually get it done and working! haha

The only thing that worries me right noe is that there are 2 wires that go to the ECU, one from the low pressure switch, and one from the thermostat switch. I am not sure if these wires are only signal wires to the ECU to let the ECU know AC is on, or if the ECU is controlling anything. from the looks of it, they are just signal wires.
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-19-2011, 11:05 AM   #52
Que89YJ
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Those are control lines the ecu to. The ecu gives the YJ owners a 33 error because we dont have the relay and feed back. I am not sure if the YJ controller is fully programmeed for the AC. There is only one way to find out for sure. populate the wires to the ECU pins and see if it works. If it doesn't the Cherokee ecu is a direct swap and should work.

You need to wire 3 wires to the ECU:
AC request
AC Select
AC Clutch
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Unread 12-19-2011, 11:46 AM   #53
youngjeeper11
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well...I was not planning on having the ECU at all....i have a 4bt....

so I was wondering if I need to jumper any of those wires together to complete a connection that the ecu would make....
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-19-2011, 12:39 PM   #54
Que89YJ
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Ouch. Well, the ecu play controller for the ac clutch. The Low pressure switch is a cut out input for the ECU to cut out the clutch. The problem I can forsee is that yes you can pull in the clutch and make it work, but the low pressure cutout and the thermostat cutoff for icing will both be bypassed and the clutch will be engaged with no way to make sure that in either of the 2 cases the compressor doesn't self destruct. I know the stand alone unit made some kind of provisions for them.
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Unread 12-19-2011, 01:24 PM   #55
youngjeeper11
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hmm... there has to be a way to do it. I mean, maybe I use the ecu anyway. I have not studied the wiring system well enough to know what I can and cant have operational without the ecu, but initially I planned to cut out everything that had to do with it.

There has to be a way to wire it stand alone, cars with carbs did it...
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-19-2011, 02:07 PM   #56
Que89YJ
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I agree. The stand alone unit that are put in aftermarket work without the ecu. I think we need to check how those are wired in and go from there. See if you can find the info for the aftermarket ac units for the YJ. I am tied up at work or i would investigate too.
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Unread 12-19-2011, 03:11 PM   #57
twiisted71
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A lot of early '80s Fords had a push button on the HVAC control panel for kicking the A/C compressor on/off. Perhaps you could find one of those?
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Unread 12-19-2011, 10:14 PM   #58
dodger889
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Ok the low side is closed when the pressure is above 12 psi if I remember correctly the high side kick out at 220psi again the brain is working hard So to keep the safety circuit in there you need to run both switched in series to a relay. Off the compressor switch on the controller. Then you figure out if the switch (controller) goes to ground or is hot when one Then from there I think you can figure out how to wire a relay for power to the AC clutch. So just to think about it this way low pressure make sure you have enough to lubricate the compressor and the high side keeps it from blowing apart. That is their only function is protection. Hope this helps you.
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A 89 yj with a 4.0 aw4 sye out of an 92xj. Now the hard part is done time to get it up in the air just a bit. Working on 8.8 with 3.73 and lsd for the rear. and new D30 hp with 3.73 .
For those who have not figured this out I'm old school but can handle the new too.
Quote:
Originally Posted by bigsquat View Post
im just cheap, and cheap makes you creative.
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Unread 12-20-2011, 05:17 AM   #59
youngjeeper11
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yea, you are correct, and they way the thermostat and low pressure swith are wired now is in series. I need to find a "typical ac wiring diagram"

I plan to use the relay already wired into the harness and power distribution center for the ac
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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Unread 12-20-2011, 05:19 AM   #60
youngjeeper11
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Quote:
Originally Posted by twiisted71 View Post
A lot of early '80s Fords had a push button on the HVAC control panel for kicking the A/C compressor on/off. Perhaps you could find one of those?
The compressor still needs to turn on and off automatically based on the pressure in the system I believe.

This control unit technically does have an ac switch, it is just incorporated in the slide knob when you select AC.
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Jeep 1:Used to have a 93 YJ 2.5l- 3.5" Black Diamond, Chevy TBI 5.7l V8, SM 465 4 speed, 8.8 rear( 4.10, L/S), rhinoline, Mile Marker 9000, NP 231, Had to sell it due to college
Jeep 2: 89/91 YJ, 4BT Cummins, NV4500, NP 231, Old Man Emu 2.5" suspension lift, 1" body lift.....Runs and drives, but very much a project
Interned at Novak Conversions 2 summers ago

Ask me about my 4BT Cummins Motor Mounts!!
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