RX-7 Logicon Repair/Replacement
Symptoms:
• Ducts do not redirect airflow when different positions are selected (i.e. Defrost, Flow towards feet, Flow towards face etc.)
• Fan does not respond to fan-speed control, or full range of speeds not available.
• Temperature slider does not adjust the mixture of warm/cold air
Solution: Resolder ‘cold’ solder joints within modules/replace parts
Tools Necessary:
• Phillips Screwdriver
• Soldering iron
• Flathead screwdriver or thin prying device
Background:
Many cars develop this problem with age. For some reason, the electronic components in the early second generation cars leave much to be desired. My car developed these symptoms slowly. Originally, the buttons would not respond immediately to button presses, necessitating either a ride over a bump on the road, or a tap to the faceplate of the logicon to engage my actual vent selection.
Eventually, the vent selector stopped working entirely. This was fine for most cases (it happened to stick in my preferred position, the ‘face’ position) but was a major problem when the windows started to fog up. So, I ended up doing the resolder job listed below.
After a while, the temperature potentiometer went south on me, as well. I ended up buying another logicon from a junkyard, and installing it as listed below. Note: It’s been mentioned to me that the symptoms of a bad logicon are almost completely indistinguishable from a bad airmix motor, which also likes to fail on these cars. If following these procedures does not help your cause, the problem could either be that you have actual component failure on the logicon PCB, or your airmix motor has gone to the great scrapyard in the sky.) Mazda likes to replace both of these when a problem arises, costing the poor consumer a huge amount of money (they like $500 for the logicon, $200 for the air-mix motor…plus labor!)
So, my recommendation to you is, try the following! It’s really not that hard, and could save you quite a bit of cash!
Get pdf RX-7 Logicon Repair/Replacement
