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Add A/C to '88 MJ


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My '88 MJ is as base model as you can get.

It's got manual steering, 2.5l engine, and no A/C

 

With the SoCal summers being real hot in the MJ, I find myself asking how can I add A/C to it?

What parts do I need? How hard will it be to complete the project? Where can I source parts for this?

 

Thanks in advance

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Ah. Another fellow 2.5L owner. 

 

Well its not hard to add AC to our MJs. Plenty of members have done it. 

 

You'll need the brackets for the 2.5L, compressor, lines, condenser, receiver, dryer, expansion valve, control deck, wiring harness, evaporator and the housing for evap and heater core. 

 

Completing such a project for us 2.5L guys is getting impossible. 

 

You can only use Renix 2.5L parts. No 4.0L Renix or 2.5L or 4.0L H.O. engine parts can be used. On the interior side, everything is the same from 84-96. 

So in short, sourcing parts for 2.5L AC is getting impossible. I’ve gone four years without AC in my truck. 

Your best bet is to post a want ad and keep an eye out for people selling whole engines for the 4.0 conversions and at the salvage yards for the Renix era and the Pre H.O. YJs as they used the same brackets for the AC. 

 

I wish you luck on your hunt.  I got lucky and a member found someone selling their whole engine that had everything I needed and they managed to snag the interior parts too. 

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Not sure how much your invested, want to be into the project and if your attached to this particular MJ. Your skill level. But if it need alot of work, rust, 2wd, no ac, 2.5l things you want or need you could always sell it and buy another with the features you want. Just a thought. 

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Thanks for the advise guys.

I'll keep an eye out for a 4.0 then (was planning to swap out the 2.5 anyway)

 

It's a project truck that's turned into a personal goal to get into an awesome eye-turning truck rather than its current base-model eye-turning truck that struggles with larger hills

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It's a pretty large project, I'm in the middle of it myself. 
Probably $500 in new AC parts and $200 in a parts jeep for the heater box and wiring.
It can be done cheaper if you trust the rubber on 30 year old hoses. There's also the condenser and evap core that are parallel flow now instead of serpentine. 
You can also skip the heater core if you want to risk having to pull everything in the future. 
Personally I wanted a system that worked well and I wouldn't have to recharge because parts jeep parts didn't work. 

Might aswell get a parts jeep and swap everything to a 4.0.  

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1 minute ago, m2bandit said:

It's a pretty large project, I'm in the middle of it myself. 
Probably $500 in new AC parts and $200 in a parts jeep for the heater box and wiring.
It can be done cheaper if you trust the rubber on 30 year old hoses. There's also the condenser and evap core that are parallel flow now instead of serpentine. 
You can also skip the heater core if you want to risk having to pull everything in the future. 
Personally I wanted a system that worked well and I wouldn't have to recharge because parts jeep parts didn't work. 

Might aswell get a parts jeep and swap everything to a 4.0.  

Do you have a detailed parts list with prices?

 

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8 minutes ago, WesD said:

What's the deal with the necessary wiring harness?  Just thinking I might build my own.

So that way you won’t have to build you own. 

If you do though make sure you use 80’s GM connectors. There should be a four plug connector on the drivers side of the engine bay hidden by the washer and coolant bottle for the 2.5L that is plugged by a cap.

I have a NOS wiring harness if you would like to see the connections. 

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Sure, when you get to the point of installing your harness, a picture of both ends and the connectors would be quite helpful.   Appreciate it.   How is your install going?   I just got the compressor and alternator bracket for mine, going to get the rest of the pieces over the next month.  

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  • 1 month later...

Any updates on this guys? I have sourced the evap box for in the dash, the controls and the compressor bracket from another 2.5L ‘87 to try to add AC to my ‘86 2.5L. Concerned about the wiring harness portion bc this was cut out of the parts vehicle I got the stuff from. I’m about to pull the dash and have a look see at how this is all going to go in. Starting to second guess myself and wondering if I’m better off just getting an aftermarket under dash setup and calling it a day. 

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Which harness? Engine side is the same for all years. Dash side is a tad bit tricky. I'm beginning my install this weekend. I have everything I need to make it plug and play. But I'm not sure if '86 has a specific dash harness.

It should be a six prong plug that plugs in some where inside the dash. The year of your truck will be quite helpful for us.

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2 hours ago, RGniady81 said:

Any updates on this guys? I have sourced the evap box for in the dash, the controls and the compressor bracket from another 2.5L ‘87 to try to add AC to my ‘86 2.5L. Concerned about the wiring harness portion bc this was cut out of the parts vehicle I got the stuff from. I’m about to pull the dash and have a look see at how this is all going to go in. Starting to second guess myself and wondering if I’m better off just getting an aftermarket under dash setup and calling it a day. 

I did a little bit of part number digging and came across that the harness for the control deck is different between '86 and '87. But it gets discussed very often on here how some early production '87's could have used '86 parts until they ran out.

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I plan to add a crap load of pics. As long as your set up is a serpentine and not V-belt, adding AC should be pretty dang straight forward. I recommend getting the AC kit from jeepair that is a R134a retrofit. 

But if yours is an '86 and you sourced from an '86, then you should have no issues with your parts. But the belt routing is important and '86 is an odd year.

I'll do a DIY for us 2.5L guys, I feel ya on the lack of documentation and pictures.

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I added AC to my 87 with an 86 donor. The dash side was plug and play, but the engine side I had to make some wiring to attach to the "dealer installed AC" plug on the driver side inner fender, as said, under the washer bottle. The dash side youll need the HVAC box and the controller. I just left the controller attached to the box and fished it through the dash when I put the dash back in. Having all this apart, gives you a good chance to clean the heater and AC evaporator coils while its out if you arent using new ones. Youll then probably need to convert the whole system to R134a refrigerant when you go to charge it. Its been a bunch of years since Ive done mine, so no pics, sorry. Its always had a small leak too. It needs charged every year. And when that compressor kicks in on a 2.5, just don't expect to go anywhere very quickly!

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38 minutes ago, dasbulliwagen said:

I added AC to my 87 with an 86 donor. The dash side was plug and play, but the engine side I had to make some wiring to attach to the "dealer installed AC" plug on the driver side inner fender, as said, under the washer bottle. The dash side youll need the HVAC box and the controller. I just left the controller attached to the box and fished it through the dash when I put the dash back in. Having all this apart, gives you a good chance to clean the heater and AC evaporator coils while its out if you arent using new ones. Youll then probably need to convert the whole system to R134a refrigerant when you go to charge it. Its been a bunch of years since Ive done mine, so no pics, sorry. Its always had a small leak too. It needs charged every year. And when that compressor kicks in on a 2.5, just don't expect to go anywhere very quickly!

Neat. Thankfully I cleaned everything. I plan to do a well documented DIY for future AC-less 2.5L owners

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  • 1 month later...
On ‎10‎/‎4‎/‎2019 at 10:36 PM, RGniady81 said:

How’s your progress coming? I finally stripped my dash and am gathering remaining parts to start next weekend. Unfortunately, I do in fact have a v-belt setup. 

 

Eeesh.  That's what I had on my 86.  That just made the sourcing of parts even more difficult.

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I have sourced the underdash box, compressor bracket, & control panel. I ordered a compressor from Rockauto for the v-belt setup & I have a local shop that’s going to make the hoses for $40. I know the control panel plugs right in to my existing harness but my one ? Is the wiring to the engine bay to kick the compressor on etc.  I assume this is ancillary wiring that I do not have since I was heat only. Do you know the story on this and if it has to be sourced specifically from another ‘86?  

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6 minutes ago, RGniady81 said:

 I know the control panel plugs right in to my existing harness but my one ? Is the wiring to the engine bay to kick the compressor on etc.  I assume this is ancillary wiring that I do not have since I was heat only. Do you know the story on this and if it has to be sourced specifically from another ‘86?  

You will need a AC control deck wiring harness from an AC Jeep of the same year. There should be a plug in the engine bay that is empty. That should be the AC wiring on the engine side. 

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