So I have a '90 vert, na 5-speed, basically stock minus stereo, K&N drop in, RB exhuast, 10k blue tag motor. Recently, the logicon has stopped moving air beyond the faintest trickle of heat (cold here, running all the way hot side) any time of day. The lights on it work, the selectors all work and I can hear the clicking and moving of parts under the dash, but no matter where the slider is I can't get any moving air. I tried to resolder the cold solder points yesterday, but I'm not a pro at it and am not going to say that I gave it a proper test. But, I've searched and have cut up arms, so I'm just gonna turn to someone who knows more than I do. Anybody got any ideas? Dead logicon? Blower motor? Blower doors? I'm lost now. My hunches turned up empty.

 

So the problem is the temperature, not the volume of air being moved by the blower?
The air mix motor and the heater core valve determine the temperature.
For the air mix motor, you can disconnect the linkage manually and move the it to the warm position.
If it's your heater core/valve, feel the tubes of the heater core and make sure they are warming up. Heater core could be clogged or the valve could be stuck closed.

I thought I was going to hate doing it manually, but it ends up I only move the temp selector every 6 months or so.

edit: Forgot to add, the air mix motor and logicon seem to take each other out when going bad. So you may have done a good job on the logicon, but the air mix motor could still be dead.

 

No, the problem is that I don't have any pressure of air at all besides the faintest little trickle of heat, regardless of where the slider is for how strong the air is, on full hot. So I do feel a little heat, but I can't even hear the air moving, and hardly feel any air moving from the vents at all. But I'll still check the heater core. Thanks for the help!

 

Does the fan blow properly if the settings were set to cool?

 

No. Regardless of where either slider is, I just got engine-temp trickles of air, and as of today I'm not even getting the warm trickle, I've got no moving air of any kind. And it may have been because I was driving, but I didn't hear the blower doors moving anymore. But, weirdly, if I hit recirc, I can hear some kind of electrical noise under the passenger dash, but then nothing changes. It makes a slightly longer electrical noise when I click recirc off, and that noise is consistent length for both on and off, even though the "off" noise is a bit longer. Any ideas? I already had to re-solder the idiot cluster, and it works perfectly now, with the exception of the minutes ****, it has never worked. Ever. Any ideas? I feel like a logicon is in my near future.

 

sounds like the blower motor

 

Same issue, except I don't get hot air if it is too cold outside either. From what I can see, the upper flapper (taking it is two in the heater) that goes to the heater rad is midway, so I get hot air when idling and when "hot" outside (32F). Also my fan sucks intermittently, so I think it is my Logicon.

From what I have read from you, it seems like the same thing.

 

Sounds like it. So logicon and blower motor, possibly. Well, *****. This is gonna be expensive.

 

Info in this link will help you figure out what the source of the problem is.

https://www.rx7club.com/2nd-generati...-works-864152/

 

Thanks for the info, man. I appreciate it big time. I really need my heat back.

 

i have similar issue.

no heat when i move the slider to hot. nothing happens, the vent only blows on my feet/face setting. pissed off.

how do u manually move the selector RXSpeed16 ?

 

Okay, discoveries. Pulled the blower motor out, the whole unit. Cleaned everything, buffed and soldered the brushes again and while it was out, continuity tested everything. Except it got worse. Now: I have no moving air, of any kind, but I can watch the recirc/fresh door open and close, but no more clicks or noises when I change the vent locations on the Logicon. Heater, ex-hi and ignition relays passed continuity tests, but I haven't bench tested them since it's 21 degrees here and I don't have a power supply for testing. I'm confused, and not quite a wizard with electronics. I have a feeling it's the brushes on the motor, even though I redid the solder points. They were rubbed elliptical on the side that contacts the motor. The logicon could still be at fault, though. But testing seems to indicate that the power transistor and ex-hi aren't at fault, or they both are at the same time. Stumped and cold. Any ideas?

 

I left everything attached because my logicon and air mix motor are dead. I snag the arm where the red arrow is pointing and move it where I want. It also happens to be the lowest point. If it won't stay there, disconnect the wiring from air mix motor to the logicon and move it manually.



You'll probably have to crawl up in there once to figure out where things are. Now, I can reach down and do it without looking. But for some reason my car will caugh every time I do it.

 

Ever figure out what the problem was? I've been having the same issues, it seems like every other day something in the Logicon/ blower department stops working...

Just changed the 7.5 fuse of 'ROOM' to a 10 fuse and now it fixed one of my problems, I can hear the doors open/close when I push the vent locations on the logicon. Planning to test the blower unit next.

 

ummmm its a certain amperage for a reason, you should not just up the fuse to make stuff work. if it keeps popping there is a wiring problem somewhere... fix it

 

I hate to resurrect an old thread, but I'm having this same issue, anyone ever figure out a solution?

 

I too am experiencing the same issues. I bought a used logicon from a member back in the spring. My issue now is different than when I bought the logicon. Back then only the "high" setting would work and it would work for both heat and A/C. I never could figure out how to get the new logicon in, despite the multiple posts that said I could go in from behind the tach and speedo gauges. Always seemed like I was going to unplug something that I wouldn't be able to get back in or break something as the gauges weren't wanting to come out very easily.

If anyone has tips on how to install a new logicon, that would be greatly appreciated. I daily drive the car and really can't pull the dash all the way out unless I can be sure I'll be able to get it back in so I can drive it to work the next day. For now I'm just dealing with the cold as I only drive it less than 10 miles/day.

If you're in the Cincinnati area and want to help, I figure I'm going to try again this weekend. I can pay very modestly for the help.

 

If the "old" logicon is installed/connected, you're in good shape to put in another:

-Remove the defrost garnish (this is the panel right next to the windshield with the vents in it, held with a small bolt in the center and clips on the ends)

-The long (stupid) pigtail from the logicon connects to the harness right at the (now exposed) firewall.

-Unplug the connector and tie a long length of string around it.

-Slowly remove the logicon, trailing the string through the dash.

-Untie the string and put it on the "new" connector, use the free end to draw up the pigtail through the maze of the dash and back into position.

Done.


BTW...
R&Ring the dash is not that big of a deal (I can have mine out in @30 minutes, working solo) and you shouldn't fear the job. The first time might be better done (if you can wait) till it's warmer (the plastic is more forgiving when not frozen) and you have a bit more time (because there will probably be a lot of broken plastic to deal with).

 

Thanks. I did try to remove that piece before but did not realize there was a bolt in the center. I'm definitely going to try it this weekend (or maybe even tomorrow) and I'll post my results for people having similar issues.

Thanks for the advice!

 

Wanted to update my post and give a thanks to Clokker for his help. I was finally able to install my new logicon with the most simple advice from him. I had never read that there was an additional bolt in the center of the upper dash trim holding it in place. Whenever I tried to remove it, I always stopped because it felt like I was going to break something (I would have). So thank you sir, for that little bit of info that made all the difference.

As for what was causing my issues, it was definitely the logicon. More specifically, the blower speed slider. Thanks to the small hands of my helper I wiggled out the pigtail and plugged the new logicon in and immediately all problems were solved. I now have heat for the upcoming frigid temps and I even checked the A/C to make sure everything was working.

RX7Club.com for the WIN!