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Retrofitting an A/C Evaporator into existing Heat/Air ducts

1K views 25 replies 6 participants last post by  moncada881 
#1 ·
Hi All,

I'm going back and forth on different ways to get A/C into the Jeep piece by piece (mostly from the junkyard) since I don't have near the $1000 for one of those JeepAir kits. There's a lot of mid-90s Grand Cherokees around here in the yards, and it seems like all the other parts besides the evaporator from that system will fit with fairly little modification.

To be honest, If I found an underdash unit at a decent price I'd just grab it and be done with it, but so far everything I've been seeing on ebay is at anywhere from $140ish (being broken/cracked/missing pieces etc) to $250ish, and I'ts just outta my price range for one part. If anyone has their old one laying around they'd be willing to sell, feel free to send me a PM :wink2:

Otherwise, for anyone who has taken apart the stock Heat/Vent ducts, is there a reasonable way or place to retrofit an AC evaporator in there? I was thinking of it utilizing or taking the place of the "Vent" half of the temperature control slider. Ie, I could have it set to Vent and the outside air would be directed to the evaporator, and then i can just turn the blower fan on.

Now I know at least someone at this point is still thinking "why not just use the underdash A/C setup?". Well, besides it being out of my price range at the moment, if a retrofit hasn't been done before, I think it'd be kinda neat to see if it can be done relatively easily. Also as I've been reading around, I keep seeing that the under dash setup makes getting back up and behind the dashboard a royal PITA.

Anyway, any ideas/experience/advice would be much appreciated. Thanks!
 
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#6 ·
I feel like I see a thread on here where someone is scrapping their AC system every 4 months or so. I imagine you can get a compressor off a Cherokee. I got my condenser from jeep air for $160 because mine had a leak I caused. My AC works great and I'm using 134a.
 
#7 ·
Ill keep my eyes peeled! I grabbed a compressor for $30 at picknpull with a 1 year warranty the other week. I'm looking at grabbing everything but the evaporator from a Cherokee or grand Cherokee; the Grands are a dime a dozen in the junkyards around here in North Texas right now.

The most expensive part is the underdash , so I was thinking about figuring out a way to put the evaporator in the existing air ducts used for the vent/heater... 😂 I think I've either asked a question no one has an answer to, or no one else seems too interested in diving into such an idea. Ill take it apart and take a look at it; if it turns into something doable ill make a writeup.

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#9 ·
You know, i just might call the guy up. $50 asking isn't bad at all, provided it works all ill need is a can of paint.

Btw, I've gotten that head real cleaned up and lapped the valves, thanks again! Right now I'm just waiting for some consecutive days off work where I can start the swap.

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#14 ·
I can't for inside the cab because it's all hidden above the unit (I connected the wiring before putting it in place.

I can under the hood. I'll pm it to you but probably won't get a chance until tomorrow. But really, it's just a wire coming through the firewall, then tied to the wiring harness to the passenger side and down to the switch on the accumulator drier on the fender next to the compressor. Then from the other side of the switch to the compressor.
 
#15 ·
I can't for inside the cab because it's all hidden above the unit (I connected the wiring before putting it in place.

I can under the hood. I'll pm it to you but probably won't get a chance until tomorrow. But really, it's just a wire coming through the firewall, then tied to the wiring harness to the passenger side and down to the switch on the accumulator drier on the fender next to the compressor. Then from the other side of the switch to the compressor.
ok so the wires that connect to the cig lighter, red and white one, I disconnected because I can connect them to the original cig lighter that is on the wiring harness. now for the yellow wire is it the one that is isolated? or the one that's with the orange and red wire, and for the yellow wire do I connect it to this area where the heater blower is?
 

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#16 ·
Looking at this picture, you want to leave the flat connector (circled in yellow) connected. It is what connects the motor to the switch assembly inside the unit.

The connector circled in red was disconnected when I got my unit. I cut the connector off and spliced in to those 4 wires. There should be a red/white one which is for powering the cig lighter, a black wire which will be the ground, and then the two wires that are power going into the unit (which comes from the heater blower circuit) and the switched power coming out that will go to your switch on the accumulator/drier.

I don't remember that yellow wire coming out of the motor which has a plug on the end. I also don't know about the plug at the heater motor. I tapped into the wire coming out of the fuse box.
 

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#17 ·
Looking at this picture, you want to leave the flat connector (circled in yellow) connected. It is what connects the motor to the switch assembly inside the unit.

The connector circled in red was disconnected when I got my unit. I cut the connector off and spliced in to those 4 wires. There should be a red/white one which is for powering the cig lighter, a black wire which will be the ground, and then the two wires that are power going into the unit (which comes from the heater blower circuit) and the switched power coming out that will go to your switch on the accumulator/drier.

I don't remember that yellow wire coming out of the motor which has a plug on the end. I also don't know about the plug at the heater motor. I tapped into the wire coming out of the fuse box.
ok I'm glad I took that connector, ok so on the connector end the only thing that changes is the cig wire, that turns purple, the two blue ones I'm guessing are the power wires? one of the blue wires has a black line on it. then theres the white wire idk what that's for but let me try to find where i can put the wire for the heater blower, you said at the fuse box so ill check there
 

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#22 ·
By switch I mean the knob on the unit. The left knob. All the way to the left is off. Turning the knob to the right are fan speeds low, medium, and high. I was talking about doing this test outside the jeep. Just hook up some test wires and clip them to the battery terminals to verify that the fan works correctly and that the (blue) wire gets power when the knob is turned on.
 
#24 ·
If the white wire is connected to positive and the ground wire is hooked to negative the fan should come on when you turn the switch on.

But I wouldn't do this until you determine which wire is the ground. If you hook the wrong wire up and turn on the switch, you'll have a direct short across the battery!
 
#25 ·
If the white wire is connected to positive and the ground wire is hooked to negative the fan should come on when you turn the switch on.

But I wouldn't do this until you determine which wire is the ground. If you hook the wrong wire up and turn on the switch, you'll have a direct short across the battery!
sorry for taking long, was waiting for my pops to bring his meter, so the white has continuity with both blue wires? and then I checked the blues with each other and they have continuity with each other too? any thoughts?
 
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