Anyone ever thought of adapting the AC/heat system?

[Wagoneerlover]

Have any of you ever thought of adapting one of the new automotive integrated heater/ac systems into these rigs? (Ie. Running it all through the vents as opposed to heat coming out of the bottom of the dash and ac coming through the vents.) The stock system seems to be pretty strong so I dont know if a heater core and system from say a 98 Grand Cherokee would be an upgrade or downgrade. (When I say core I mean complete AC and heat system.) I am not up oin the tech side of the AC system so dont know if the grand cherokee system is stronger or worse then the existing system anyone out there have any ideas/ thoughts?


Maybe the stock system could be modificed so that AC and heat come through the vents. I only ask cause my AC went south (New compressor and expansion valve needed) And I have reason to believe that my heater core is failing. There is a wrecked 98 Grand Cherokee a few houses down and the guy is willing to let me pull the ac/heat components before the insurance scraps the rig.

Even though the parts would be free I dont know if trying to adapt it to my rig is worth it. Anyone have any Ac/heat output specs etc.

[BigRedChief]

I'd say try it, at least. See what you can come up with and let us know.

I've been interested in something like what you're talking about too. I don't know what system would fit and work well in our Jeeps, but it would be nice to have everything a little more compact than it is now.

[710 Burner]

Having the AC remove moisture from the defrost air would be a plus.

[TexasJ10]

I have scoured the junk yards several times for something that would fit in the area behind the dash in an FSJ. It seems that all "modern" cars have dash boards that extend much further away from the firewall than our FSJ's. To compound the problem, a lot of modern cars have the majority to the routing controls and dampers in the center of the dash. That is the area on a FSJ that is pushed into the passenger compartment to allow more engine room. I thought I had found something that would work out of a GEO. It was really compact and had a huge A/C evaporator and heater core. Unfortunately, when I started trying to fit the components, I only had about 5" of space for a blower, and I needed between 7" and 10".

I have started to look more closely at whether the factory A/C unit can be adapted to provide heat and defrost while routing the A/C through vents in the dash. It doesn;t look too practical. I have removed the heater box out of every FSJ I have because I hate the real estate it takes up. I'm running a Vintage air unit in my daily driver, and may break down and get a Hot Rod Air unit for the J20 project. It cost me $200 for the Geo set up at the junk yard that didn't work. It costs less than $400 for the Hot Rod Air in dash unit. Fortunatley I got a credit at the junk yard for the old Geo stuff. If someone finds something else that will fit I would like to know as well.

[Kenall]

I have installed 'AC only' Vintage Air systems in both my wags. I choose at the time not to remove the OE heat/defrost system as it was functioning properly and time was short during the two install periods.

Vintage Air does have complete HVAC systems that would install under the dash of FSJs. This would eliminate the core box in the engine compartment and bring owners up to 134 freon.

I opted for all new parts rather than reusing OE installed r12 parts. My ace in the hole is the install of SBC engines prior to AC installs. This allowed a larger selection of compressor bracketry.

[Wagoneerlover]

I think I might give the grand Cherokee AC system/unit a shot and see what I can come up with. Eh its free so if I fail I can always junk the parts and go back to the drawing board. Hopefully one day one of us will come up with a solution. When adapting these rigs you just come across one jigsaw puzzle after another.

[malodin]

if all alse fails you can put the heater a/c system on c/l or ebay im sure

I think I might give the grand Cherokee AC system/unit a shot and see what I can come up with. Eh its free so if I fail I can always junk the parts and go back to the drawing board. Hopefully one day one of us will come up with a solution. When adapting these rigs you just come across one jigsaw puzzle after another.

[Warmachine]

This really got me thinking...Might have to start tinkering around with this idea. At the very least, I think I'll fab something up to replace my ashtray and clock with vents....hmmm. Anybody else seen/done this?

[Wagoneerlover]

I am going to give the heater box from this grand a whirl. I have not gone to pull it from the guy yet as it just snowed for the first time in maryland and it was freezing cold outside. Will try to dig into it soon and see what I can come up with.

[Allen78J20]

I was thinking of just getting a square flex tube, hooking it to the duct on the floor, then make an opening in the back or bottom of the ac unit,and connect the two. That way when I direct it to the floor, it blows out of the ac vents. The floor vent is great, but my center console is in the way. Sounds good in theory!

[Warmachine]

What I was thinking was making up a new plenum <sp> box that would sit on top the current box. Would have to be small enough to sit behind the radio, and connect directly to the defrost ducts...small air dampener like in the heater core air plenum, cable operated. Out of the same box would run two air tubes to the vents mounted either side the radio. My passenger side fresh air vent has been disabled by the PO, so I've got a cable/knob just sitting there. Push the defrost button, and pull or push the old fresh air vent knob for face/windshield selection...adjust the fan speed and enjoy the luke-warm blast from the old ashtray hole...what do you guys think, worth the effort?

[Wagoneerlover]

before I begin to dig into the project I wound up tracing the wiring harness. It seems that some of the HVAC units controls from the Grand Cherokee come from the powertrain control module. I dont know if there is a way that I could bypass some of these controls or add an outside controller as I dont really know which functions the PCM provides and which ones it doesnt. That is going to be the huge headache area in most new vehicles. the fact that the pcm provides at least a few if not many of the HVAC control fuctions from within. Without knowledge of exactly what is going on, I doubt that I could use it. Possibly I might be able to wire up the system so that I have the PCM from the Grand cherokee installed in the vehicle and powered up/getting power but only linked into the AC system for the purpose of controlling the A/C. Seems to much of a headache though just to get A/C/ functions as it would add an additional computer that I would have to integrate into the system assuming that I could even get it to work. (I.E. it also uses data from other sensors to perform hvac functions including the temp sensor, and various other sensors that the HVAC unit uses for different operations.)

[Warmachine]

Don't go quitin' on me now! :D I dig the idea, and with the extra room behind my passenger side dash area, something should be workable. Off the top of my head I can only think of a few vital sensors and what-not needed for reliable operation...Frost sensor, low pressure sensor, A/C clutch control...I suppose there are a dozen others I don't even know of. Still think it's a worthwhile idea.

[Kenall]

The floor vent is great, but my center console is in the way. Sounds good in theory!

I have a thin sheet steel deflector resting on the nose of my console, that deflects the floor vent to ea side.

[Wagoneerlover]

10-4 on the sensors warmachnine,

however the one additional problem that exist is that some of the relays, and sensors are actually built in to the powertrain control module. for example one of the a/c high clutch sensors is actually inside the PCM computer, and there is another sensor the something relay built into the PCM as well. I am sure that without these functioning properly that the a/c system will not work properly. This would mean that I would have to use "fake" sensors to replicate the signals or I would have to somehow find out what functions these sensors have and replicate it using actual new sensors wired in somehow, or I could wire in the PCM itself to the vehicle and have it actually work as an A/C/ only PCM. I know with some of the newer pcm's however that if they dont sense the engine sensors etc etc then some of them shut off supposedly. That is my only problem area. lastly to add to it the new a/c systems, store trouble codes in the pcm so if I intend on actually using it I would have to also wire up the aldl cable into the driver compartment so that I could retrieve the trouble codes should the a/c system fail. Is it possible?? who knows? but one member here is willing to try!!! and that is me!

Basically what I am proposing here is using the grand cherokee pcm for A/C control functions only. it will not control any of my engine control functions or transmission functions. so it will need to be wired in to get power and I will only hook up and install the ?ac wiring to the pcm. I will not wire in anything else. This is all assuming that I can get the A/C and heater box to fit in the wag properly.

[Dr Teeth]

This really got me thinking...Might have to start tinkering around with this idea. At the very least, I think I'll fab something up to replace my ashtray and clock with vents....hmmm. Anybody else seen/done this?

I'm going to be putting a Vintage Air complete system in my 71 wagoneer, I know that's not the main point of the thread, but the question above about the vents... I will set it up so that I'll have two center vents that replace the two stock ash trays to the right and left of the stereo and then cut two vent holes (rectangles sitting vertically) at each end of the dash where the two cowl vent controls are located now (If I do want cowl vents later, I'll just reroute the cables and controls to the right of the ignition. I'll reuse the stock defrost location and vents.

Todd

[Warmachine]

Any progress with this idea?

[Wagoneerlover]

Any progress with this idea?


Not yet. Getting the tbi system up and functional right now. The rig is down so nce I do it then I shall begin to strategically plan out what to do with the A/C system.

I will keep you all updated!

[pb]

I was thinking of just getting a square flex tube, hooking it to the duct on the floor, then make an opening in the back or bottom of the ac unit,and connect the two. That way when I direct it to the floor, it blows out of the ac vents. The floor vent is great, but my center console is in the way. Sounds good in theory!

What he said. It would probably be cheaper and/or easier just to tie the two ducting systems together in the dash. Probably would have to run the fans on higher speeds to get the airflow with the combined systems unless you put some dampers in there. Or I could be wrong altogether :huh: