So who's an expert on the hvac system wiring? I found a bunch of threads related to blower motors not working, but none seem to have a solution for me.

Basically the whole system is dead, no speeds work, temp control does nothing, selector slider does nothing.

The car has been a work in progress for 3+ years. I know that the blower worked properly at some point but I have no idea when it stopped working.

I disconnected the single light green/black stripe wire on the blower box as shown here:



And when I apply voltage to both sides of this connection, the whole system works perfectly. I'm thinking of running it like that for now since it works fine, but I'd like to get it working properly.

I've replaced all the parts shown here in this image, as well as the logicon, blower motor, and blower circuit breaker. None made any difference. I also noticed the car was missing the 'hi-speed' relay entirely, which has been added now.




I'm trying to get the car on the road this week, so any help is much appreciated!

Any ideas what else the problem could be?

 

did you replace the logicon with a known working one?

 

I have two, tried both. I guess it's possible that they both went bad, but both were working previously

 

I guess my question is, what is the main 'TURN ON' signal for the whole system?

 

Strange, my car is missing the EX-HI relay as well, after hours of trouble shooting my blower motor system, I ended up placing a jumper in the connector for the EX-HI relay, just for temporary use, it only works on one speed; maximum.

 

If you haven't reviewed this thread then do so and pay attention to what Hailers says.

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

 

i did read through that thread previously, i'll take another look though

i spliced a new switched power source into the light green/black wire, and everything works now. i'll dig deeper into it next time the car is apart, for now I just want to drive it

 

finally solved this. the B/R wire on the 8-pin the F-50 connector came from the starter cut relay (the car was originally automatic). All the auto wiring was ripped out, so that wire no longer went anywhere. I think the point of that wire is to turn off the fan to reduce load during cranking, and since it was cut, the HVAC system thought the car was ALWAYS cranking.

Grounded that wire out and all is well in the world, i just no longer have the 'disable while cranking' function