Kerok

Just wondering if anyone has any troubleshooting tips for fixing my heat in my 87' RX7. I took it over to a local shop that works on my car every once and a while and they were giving me the old, "Oh.. lotsa work here" and didn't seem like they wanted to help me. The one dude there figured it's the hot / cold selector not switching, but that seems odd to me. He said that the hold / cold selector is run by a small motor which opens and closes the door to allow hot air in... He thinks that the door is stuck in the cold position. My blower motor is brand new and is pumping cold air in with a very small trace of heat when my car is parked. The second I start moving the air through the front end turns that trace of heat into freezing cold air. The dude at the shop was sayin' that he'd have to take the dashboard out and the console to see if he could manually switch the door and check if the motor is working..I'll do the work if that's the case, but for some reason I don't think that if the door was jammed only letting cold air through, that I would feeel as little heat as I do. (you'd figure the heat would push it's way through a bit more then that.) But I dunno... Please help me as it's gonna be another very cold Canadian winter. Brrrrrrrrrr.....

nopistons

Does anything change at all when you move the sliders on the logicon? More/less heat, outlets change? Any response at all to a change in the controls? If so, it could be bad solders in the logicon, a common problem in our cars. Are the indicator lights on in the logicon? If not (this happened to me) try wiggling the ignition key (with the engine running) back and forth, but not enough to turn off the engine. What happens is that the contacts within the switch that control power to the logicon get dirty, and the logicon will retain the last settings before the power to it was interuppted. And, yes, it could also be a bad air mix motor.

nopistons

Oops - a Typo on my part. That should have read "If NOT, then it could be bad solders in the logicon.

Icemark

Sounds like a bad Logicon, I have rebuilt ones available on my website or can rebuild yours for you.

Kerok

Nothing changes at all when I move the hot/ cold slider... some of the logicon's lights are intermitent, I tried jiggin the key a bit and it didn't seem to change anything, but I assume now that's it's the logicon?? the intemitent lights must mean there is a bad solder... Thanks very much for all the help.. I guess I'll try removing the logicon first and checking it out,(any tips on the best way to remove..???) then move on to the air mix motor... Any pics or tips on how to do a quick test and rebuild on the logicon would be greatly appreciated. I would totally just buy one from you Icemark, but as always I'm totally broke...

Edit: Can you hear the air mix motor at all??? Where exactly is it located????I keep thinking I'd be able to hear it when I move the slider, but it seems totally dead.... nothing happens at all.. if there is a bad connection I figure that it would at least kick on once and a while...but maybe not... Thanks again all..

Icemark

Air Mix motor is above the accell pedal.

Search using my name and Air Mix Motor and you should be able to find the test procedures if you don't have a shop manual or downloaded shop manual.

Kerok

Koo.. thanks again man... So I just went and checked for any sound from the air mix motor and there's nothing to be heard, although I can hear the motors loud and clear when I switch defrost/ feet/ face selector switches. Do you think it's likely that the air mix slider is the only thing not working proper on the logicon or is it that the air mix motor is shot??? I read in your other posts that if you install a bad air mix motor you will blow the logicon..and visa versa... Wouldn't that mean that I have to fix both of them considering one probably went dead and the other took a hit as well ??? I guess I'll try testing the logicon?? or pull the air mix motor...?? Which do you think first Icemark???

Icemark

Well, a bad logicon only occasionally takes out a Air mix motor (usually only if a screw has come loose from the face inside and shorted the main board). But a bad air mix motor will take out a logicon almost every time.

There are a couple of Transistors that die inside the logicon when a logicon fails. I do occasionally see the slider go bad, but a good indicator of a bad slider is that the slider works in some positions (say 3/4 of the way to hot, but not all the way to hot).

Conversly a cold solder joint will generally also work intermittently, usually fail first when the car is cold, to eventually failing 99% of the time regardless of car temp. I don't think I have ever seen a cold solder joint failure that stopped the air mix motor from working without the lights in both sliders not working when the parking lights are on.

Kerok

The lights in both my sliders don't work at all... they've never come on. The lights for the selector buttons work except for one...and it's intermitent, and the fresh air intake button light is also intermitent, the ac button light doesn't work...I guess the best thing to do is rip out the air mix motor and make sure that's good, and then work on the logicon... cause if i go to all the trouble to fix the logicon and toss it back in, I'll have to redo it all if the air mix motor messes it up....What's the best way to get at the air mix motor??? I assume I should take the dash off.?? it doesn't look like I can get to it above the accel pedal...You got any pics or anything what I'm looking for..? Can I manually move the flap which the air mix motor controls?? I still haven't seen any of this yet, I'm gonna start to tear it apart tomorrow... Any last advice or a quick step by step would be amazing. I also seem to have lost my manual and I'm having a hard time finding a downloadable manual... I very much appreciate your time... thanks again man... you rule....umm.. and if the air mix motor is toast, is there a way to maybe refurbish that as well.. or maybe replace with a different motor of some kind or even jam the flap to only allow hot air to come through as a quick fix for now.... ?? I wish I was in CA.!!!

Icemark

It was 34F this morning when I got up... so CA doesn't mean warm.

There are links for the manuals in the FAQ for FC sticky thread at the top of this section.

I would test the air mix motor before attempting to remove it. Once you get the logicon out you can get to the plug pretty easy. You can get it out without removing the dash, but it does require a small screw driver and flexible hands.

Kerok

Thanks again man... I will work on testing the air mix motor today... I hope it's just the logicon...(pleeeease be the logicon) Umm.. kindof a nOOb question but what does the HEATER fuse in the kick panel control.??? The shop I was at said that the fuse is strictly for the blower motor... I found that pretty stupid that they would call it HEATER and not BLOWER MOTOR.... Is that true...?? The dude at the shop said he tested the fuse but I don't think he did....

Kerok

Umm.. I'm having a hard time getting any slack off the cable that's connected to the air mix motor to even pull the plugs on the back of the logicon to test it.. Is there any way I could get a bit more slack without taking the dash off? I can't really reach in anywhere else to trace the cable back and give it some slack... and I don't wanna take the dash off yet unless I really have to...

Icemark

On top of the air mix motor, the cable is held in place by a twist tab.

But either way, there is very little slack on that cable without unplugging it.

You do know that you can get to the plug a half dozen different ways without removing the dash pad; right???

Kerok

Can I get to the air mix motor from above the accel pedal by the steering column??? I'm tryin to get to it from there...I'm kinda working in the dark.. I need to bust out the flashlights.... too bad I don't have a garage..

and don't I also need that cable connected to do the test????

Kerok

Thanks again for all the help.!!! I found the air mix motor and just cranked the control arm over to open the flap for now at least...heat's blasting now!!! I can barely reach my hand in there between the motor and the steering column... I gotta find a really skinny handed dude to hop in and disconnect the cable and I'll try testing it tomorrow still and see if I can do anything to get it going, if it works then I'll work on the logicon..( I could hear screws rollin around inside )I'll probably just end up buying them from you though when I get some dough.

BigPimpin'

iTrader: (5)

Man, I'm having the same problem, no heat. I can press the buttons on the logicon to change direction of the air but the slider does nothing. I guess that would be the logicon?



Glad to see ya got heat!

Icemark

you can remove the gauges and get to the plug (my perfered method) or you can remove the top front panel of the dash to get to the plug.

Both are infinitly easier than trying to get at it from below.

Kerok

Thanks man.. heat rules..!!! Are you talking about the air flow slider or the hot cold slider??? Is your blower motor working, is cold air blowing out? If so try moving the control arm on the air mix motor assembly just above the gas pedal, stick your head under there.... when you look up the air mix motor assembly is mounted on the left and a small rod connects to the flap which opens and closes for the hot and cold, controlled by the air mix motor. Push the rod up and you will hear the flap slide over. Then fire it up and presto... you should have some tasty hot air blowing. (that is if everything else is working.. blower motor, heater core, etc.) Make sure you read through the threads and refer to Icemark's posts, he explains the logicon / air mix motor troubleshoot and testing....