Hello everyone, I am currently attempting to get my air conditioning working in my fd but am running into issues. My system was not working because of a punctured line so I removed the line and had it welded shut before putting it back in. I pulled a vacuum on the system and it held for 2 hours so concluded the system was leak free. I then started the car and clicked the a/c button but it did not light up and the power fc did not get a signal. I then noticed my recirc also did not light up. I have done the power fc a/c mod but still cannot get the button to light up or give a signal to the power fc. I have checked the relays and fuses so I’m currently stuck. If anyone has run into a similar issue or can point me in the right direction please let me know.
Thank you,
Eric

 

Get a PDF of the Mazda RX-7 1993 Body Electrical Troubleshooting Manual and look at section G.

It has step-by-step diagnostic procedures for the HVAC system.

My first guess would be the pressure switch - but there are many possibilities.

 

OP - I'm assuming you recharged the system with the correct amount of refrigerant after you repaired the punctured pipe and evacuated the system to leak test it? You didn't specifically say that in your post, but obviously the A/C system won't work without any refrigerant. Basically if there's no refrigerant in the system, there won't be enough pressure to trigger the pressure switch which will electrically prevent the compressor from running.

 

My first guess would be the thermo-switch right behind the glove box that probes into the evaporator. If you jump that - does the Power FC get a signal? (https://www.rx7club.com/3rd-generati.../#post10389876)

Really we should probably start at jumping the compressor to verify the magnetic clutch is operational...

 

Yep, AC won't light up if the system is empty if you are still empty/in vacuum.

Dale

 

Thank you all for the help, I now have function a/c in my car for the first time and I couldn’t be happier. Thank you @moconnor for introducing me to the electrical troubleshooting manual. I did not know such a manual existed. I ended up adding a bit more refrigerant and the compressor kicked finally. I then topped up the refrigerant and my ac is blowing cold now.

 

Nice! The AC works SO damn good in this car when it's running like it should. Such a shame that so many have just been ripped out.

Dale

 

OP, were you still running R12 or you have converted to R134?

 

I am running R12a refrigerant in the system. It’s designed to run in R12 systems but be less ozone depleting. I’m not sure how it compares to real R12 but I think it works well. I had to convert the R12 fittings to R134 fittings though to fit my manifold gauge.

edit: spelling and grammar lol

 

What product are you using to convert he fitting? Mind sharing a link? I have yet to find a quality product to convert the fitting...

 

I’m using micro trader fittings. I’m not sure how their quality is but they fit and don’t leak for now so I’m happy. I found them on canadian amazon so I’m not sure if the link will help but I’ll include it anyways.

Micro Traders R-12 to R-134a High...

 

That looks like a good way to do it. There are some that use the stock Schrader valve, many times that's one of the sources of the leak on the car. You want a setup that you remove the original valves and put those new ones on with their own Schrader valves.

Dale