I know this is quite an m.net need, but I don't go there, so i'm starting here.

SO , in efforts to repair the AC in my car,After finding, and buying ancient R-12, Learning the wiring diagrams. I found the problem...

No signal to the AC relay from the ECU. Pop The top on the ECU and clearly find a burnt out resistor... Im rather certain that this is killing my ac circuit.

I know im a *****, but i need my recirculated AIR... Been without for more than a year. so its time to repair.

Does anyone have a ECU they want to sell?

Specs..
90 Manual trans , Car has AC, HAD Power steer, Had Cruse.

Labels on box. b61p 18 881a

If its any consult, I would even trade my current ecu, to someone that wants to keep it as a backup... it still runs my car great. Been running fine for years. Would keep another car going too.

SO please, Let me know what you can do. PM's preferred.

Lets not turn this into a "EHH JUST GO MEGASQUIRT" .. AS this is my daily driver, and i don't want the forced headache of learning MS, not to mention my wedding next month.

 

You can cheat to get the A/C on without a new ECU. Splice a jumper in between the light green / black wire at position 1Q and the blue / black wire at 1J. This will force the compressor to turn on anytime you have the cabin fan running and the A/C button depressed. Your condenser fan will still operate normally.

More detailed info: https://www.miataturbo.net/megasquirt-18/great-c-faq-20954/

 

BTW, which pin of the ECU is that resistor connected to? It looks like 2K or 2L, but that doesn't make any sense.