msmcgill

My A/C quit working a few years ago. When I push the A/C button, the light comes on - but nothing happens. I can't hear or feel the A/C compressor kick on like I used to. I checked the fuse and it is OK. Could it be a bad relay? Does anyone have any troubleshooting suggestions? Thanks!

Rx-7Doctor

iTrader: (13)

Probably low on freon, 2 choices retrofit it to r134a yourself or take in for an ac service.
Warning r12 is worth more than gold. You may or maynot have a big leak somehwere that will need to be repaired. The receiver drier should be changed no matter what type of service you decide to have done. rx7doctor

msmcgill

No doubt the refrigerant has leaked out by now - but how do I know if the compressor still works? Shouldn't I see a drop in RPMs or hear it kick on? I'm getting nothing.

Rx-7Doctor

iTrader: (13)

When the freon level gets too low it will not let the compressor come on, this is to protect it.
You can run a jumper wire from compressor to battery to make sure it still engages, but do not let it stay long unless you are attempting to recharge it. rx7doctor

msmcgill

That is exactly the kind of tip I was looking for. I couldn't find anything in the Mazda workshop manual about troubleshooting the A/C. Thank you very much for the advice! I will give it a try. I read something in the forum about a freon conversion kit at Walmart. I'll dig a little deeper into that, too.

rhinor61

The reason there is nothing in the FSM is because it is a supplement manual from Mazda on the AC.

Converting from R134 is not that difficult to do, but you will to determine where your leak is. My compressor front seal and the double hose had a oily spots on them. You will also need to determine if you have Factor Air conditioning or Dealer installed airconditioning. Get to that in a minute.

I started out by blowing air threw each hose to remove any trapped oil. Then I replaced the compressor seal and the bad hose, installed a new dryer and put on new o-rings that are R-134 approved. The entire R-134 o-ring kit, compressor oil, new dryer and with 3lbs of R-134 was about $85 in parts.

Since R-134 runs at a higher head pressure, my buddy recommended that install a mazda 626 electric AC pusher fan that comes on when I turn on the air. So I got one, made some bracket and installed it in front of the condensor coil, wired in a 20amp circuit breaker, relay to switch on when I push the AC button.

Drove over to a friend house who has the AC vacuum pump to pull a 29 psi vacuum on the AC system. Takes about 45 minutes to pull it down. He hooked up his gauges to the compressor with new R-134 port fittings, after 1 can in the system he had me start the car. Constanly looking at the gauges and reading the thermometer that he stuff in my center vent.

Anyways, one he was all done with the R-134 charge, he was able to get 37.8 degrees F of air coming out of my vents with the blower on low/recycle mode.

WOW!!!! I was amazed on how good it felt driving down to SevenStock on Friday, sitting in 100 degree heat.

Find the leaks and fix them.


John

msmcgill

Great information John. I appreciate it. Yet another good project to add to my list. I am the original owner of my RX-7 (159,670 miles without a rebuild). It came with factory installed A/C. How does this make a difference? Looking forward to working A/C again - it's been unusually HOT in SoCal recently.

rhinor61

Are you sure it is factory air, most Rx-7 had dealer/port installed airconditioning. The hoses, compressor and dryer are different. Post a picture of your engine bay I will tell you for sure. Or post the name on your air compressor.


John

msmcgill

It is a Sanden Corp Model SD-575. Thank you very much for taking the time to help!