Is the Logicon...
 

Is the Logicon inside the unit in the dash that has all the temp controls or is the Logicon located somewhere else? I want to resolder all the points on it cause my heater isnt working.

It is the thing with the controls on it...and they're kinda flakey.

http://home.rmci.net/panther/rx7logic.htm When you have the board out and are soldering, look around for any overheated area. A couple of us have found that condition around R16, R-11, and D14. Also if you go to the free download 88 factory manual, you will find in the electrical section a trouble shooting tree for several failures and also a guide to jumpering the correct wires to see if the air mix motor and the mode motor are working. I'm jinked on the Logicon and the only fix I ever made was getting one out of the junque yard. Even one of those was a failure in the same mode as the one that was broke. Mazda made more than one bad Logicon with the same problem.

Thanx guys, I'll let you know if i have any success.