Logicon Nightmare
 

Got a 1988 convertible with only 31,000 miles on it, doing a full restore, motor is fine, runs great, just doing the down pipe and resonator to replace the cat and doing the K&N intake as well. So this car is mostly for show and cruising around, new paint, new top, new seats, new carpet, ect. The woman is a diva so she needs a/c and it worked fine until now. I had a local mechanic pull the dash and fix the heat, the original logicon would not send a signal to the air mix motor so i had to crawl under the dash to move the damper manually. So the car was gone at the mechanics for a couple of months for him to get the dash off of it, find one of two spare logicons i had that worked and then finally put it all back together. At least he didn't break anything that i know about, i previously took the car to the Fon du lac Mazda dealer who claimed they had RX-7 experience and i even showed up with the factory shop manual but the RX-7 expert only managed to break my dash surround and proclaimed that they couldn't go any further for fear of breaking anything else and then they charged me for the service as well.
So i finally get my car back from the mechanic, heat works great, no A/C! Previously it would freeze you out of the car.
Is there anyone who knows how to fix logicons or do i have to spend the $1500+ and buy a new one?

Typically the solder joints fail internally due to cold solder joints. They can be repaired if cold solder joints are the issue, and many have had success in doing this. Personally, I would buy a known good used unit if you are unable to repair your current logicon.

Faulty electronics
 

Unfortunately the previous post is correct the problem is likely “cold solder joints” this is a condition where the soldier seperates from board or components and causes no or intermittent connection. I had this issue with my clock unit. I simply removed the unit and reflowed all the solder joints I could find. The clock unit functions normally now. If you want this nightmare to end I recommend repairing the unit you have or find one that has been repaired. Any “working used” unit you find will likely have similar issues in due time if not immediately due to being removed then reinstalled.
good luck! I feel your pain! Restoration can be a bitch but it’s worth it to see these cars in these purest form!

You can probably find one for cheaper (https://www.rx7.com/store/rx7/fcspecials.html).