Ok, over the summer I replaced my dead motor so it could be rebuilt. While we were in there we pulled the A/C and all relevant pipes, condenser, and hoses. The hoses to the heater we left attached and connected as they should be, but now its getting cold in TN, and my heater doesn't work. Normally wouldn't be that big of a deal, I'll wear a jacket, but my windshield wont defog either and that I NEED TO HAVE work. I've heard rumor of a valve that actuates to stop the flow of coolant when the A/C comes on, however, I've found no such thing in any of the FSMs but then again I might have just looked in the wrong place. I followed the hoses out the driver side of the motor into the firewall and out the passenger side of the firewall back to the radiator and found no such valve or bypass. Any ideas? I'm sure I'm not the only one to rip the A/C out of their RX. Suppose I should tell you guys its an 88 GXL.

 

mine doesnt work either, if you find a solution to this please let me know!!!
i had ice on my winshield the other morning and regular air takes forever to defrost, plus its cold brrrrr!!!!

 

I'm guessing you had heat before?

With the car off turn your key twice so that everything electronic powers up. Now move your logicon dial from cold to hot or vice versa just once. Do you hear the door moving? It is pretty soft but you should be able to hear it. You my just need a new logicon. (Or a resoldered one.)

Otherwise your heater core may have bit the big one. I just replaced mine in November. Get ready for some dash removin' fun!

Good luck!

Cheers,
Cody

 

Replacing the heater core is not that bad. Only one panel has to come off, and you can get to it decently laying on your back and reaching up past the pedals. Take the seat out if you really want some room.

If it is in fact a bad core, and you don't have coolant the floor (that's what mine did ), then the only other way I can see it being bad is if it's plugged up.

I'd actually start with the logicon and the motor that changes the air direction to allow heater air to come through. The heater valves are also an option.

 

Is there any air at all or nothing? If you're just getting cold air regardless of the temp adjustment slider, there's a pretty easy fix for that. Let us know

 

Okay its not fixed but its working enough that im ok. Heres the deal either the logicon is bad, or the motor that moves the hot/cold air door is bad. My fix for this was to manually move the slider to allow for hot air flow. In a few days I'm going to pull out a 9V battery and test the motor, as the Mazda logicon test is $$$. I'll let everyone know what happens but from here on out my situation is unique. I'm sure some one will come in this thread and tell of a DYI logicon test/repair, but for now thats where things are. adoresrx7 I would tell you to get inverted in a very uncomfortable position on the driver side, and look for the heater core, there is a small electric motor attached to a lever move the lever (cant remember if its up or down), but move it to the opposite position that its currently in. If this doesn't fix your situation then your problem is else where.

 

thanks i will deffinately check that out!!!

 

I'm just glad i didn't have coolant leaking out of it. We'll see how it works tonight while I'm working.

 

I'm really intrigued by this, have you ever actually changed a heater core that way? I know that repair manuals say you can do it but when I went to change mine it seemed impossible without removing the entire dash.

Cheers,
Cody

 

good thing my dash was recently replace from maroon (ugggggllllyyy) to grey(purdy) and i only bolted it on half *** lol, although i hope it doesnt come down to having to take it off a second time, (major pain in the ***)

 

wow i have the same problem'ish i think i had air to flow once then it stopped and nothing will blow so i will watch this thread as well for update's

 

yo guys I HAD the same problem and it only took me 2 seconds to fix and it was free. If you want heat really bad, like I did, just go under the driver's side dash and reach way up under the dash. You will see and feel a small lever on the heater. Pull on this lever and it will let the hot air into your vehicle. Good luck. It worked for me and I still have heat everyday!!!!!

 

that sounds too easy to be safe/true/correct. has anyone else done/heard of this?

 

Safe: Yes, unless theres coolant leaking but thats not what where discussing.
True: Yes, its what I did to fix mine
Correct: To a point. This does not FIX the problem it only allows for use of the HOT/WARM air depending on what is actually wrong with your car it may actually be something else. For instance if your blower is bad, no this will not help you. For instance if you can feel air blowing on you but it doesnt ever warm up (even when you move the slider on your logicon[hot/cold selector]) then YES this is CORRECT.

its important to note though that while this allows for HOT/WARM air, this solution does NOT actually fix the problem, which still exists. It is only a TEMPORARY answer to a chilling mystery (lol a pun), but it does get you warm air.

 

if you have no air flow I'd check your blower, if that works check out DIYs for logicon testing, unless you have money which as an FC owner, no offense i'm one two, you probably don't. But if you are one of the rare ones that does go to Mazda have them test it. Just pull out some $$$ if you go or maybe $$$$ I dont know I'm poor. Gotta love college.

 

T.T all my interior is maroon T.T but at least my car runs! I think im going to swap all the maroon except for the floor and roof carpet, the hatch carpet is getting replaced and if I can find a panel kit for my car ALL OF THEM, INCLUDING THE DASH, are going!!! Where did you get your replacement? Junkyard, or AM?

 

thanks for the help guys it worked, for the rest of the winter i will have heat!
and for the summer, AC.. so thanks for your help.

 

i got my dash from the junkies, it was a bitch to take out but well worth it. the maroon is uuuugggly, i found a black vert at the junkies too, im going to scoop up some side panels and stuff from that one too. going to be black and grey theme.
the floor was pretty easy, if you have the **** maroon i would switch it out. and the roof, im still thinking about how im going to do that. not looking foward to it but the maroon has gottta go.

 

the carpet if i rip it up will just get redied to a crimson, the hatch carpet will go black and asfar as the roof carpet i'll probably pull it and if i can't find a rx with black roofing i'll just do a custom lay. thats going to be fun i bet, lol just kidding its going to be hell

 

yeah i want to take the roof carpeting out sooo bad, i havent really looked at it tho to see how hard it would be, do you think it would affect my sunroof from working properly? i just fixed it so im scared lol.

 

wouldnt know, i dont think so but hey carpets magic these days what was it doing in the late 80s you know. I don't think its going to hurt anything its not like its holding the car together, quite the opposite if its matoon, its the only thing that makes me want to get out of the RX7.

 

yeah lololol. i feel like an old lady when im driving, with my marooness. lolololol

 

Bump.

So I'm having the same problems. I removed the AC + my heat only works after 4k rpms. I took a look underneath my dash while I had the key on and moved the logicon from cold to hot + saw the flap moving. I don't have any coolant on my floor either so I'm somewhat confused as to what is wrong.

 

Wow two things that come to my mind, one have you/some one else ever over heated any motor thats been in that car and two, check your coolant level.

my theories, just theories, one if a motor has over heated, the coolant crusts and cakes on areas of connection, so your flow is really slow. Two probably a more likely story, if your coolant level is low again you wont have enough flow until get to higher RPM. if your logicon is working those are the only other things i can think of except maybe the blower, do you hear the blower turn on?

 

oh yeah, fixed my damn heat problem then two weeks latter i lost gears 1;2;3;5;R, its not fair!!! Yeah it is just part of restoring 20 year old cars right?