'91 Miata A/C Compressor not working

I had my A/C system converted to R134a and recharged by a pro.

There is power going into the connector on top of the A/C compressor, but not coming out, even with the system charged properly and everything turned on.

What does this connector control and is there a replacement available? Someone on m.net mentioned that it may be a protective thermoswitch to prevent overheating. Anyone here have an idea?

Thanks in advance!

In reply to CGLockRacer:

You need to see if you have power going to the clutch coil... My sis-in-laws Miata is the same way. I just haven't taken the time to crawl in there and find out...

On a 94, the connector is 1 pin. The connector is used to energize the magnetic clutch. If there is 12V, then the clutch should be engaged.

Check to see if the coil has the proper resistance. I believe you can buy replacement magnetic clutches. I went through this and bought a clutch, only to find out that I was low on refrigerant. I have the clutch sitting in a box. I'll have to check if it is compatible with a 91. The 12V signal to the clutch can be interrupted by the low refrigerant switch, or an icing switch.

The sensor on the compressor is the high pressure switch. At about 325 psi it will cut power to the clutch. If its not sending 12v to the clutch it could be bad.

Try jumping those wires to send power to the clutch. Then borrow a manifold and let us know the high and low side pressures.

UPDATE: So I jumped the connector and everything now works fine. I'll just run it this way until spring. The only reason I would need A/C now is for the defroster.

So can I remove that switch on the compressor without discharging the system?

Also, does anyone have one of those switches (it's held in with 3 phillips screws) laying around?

I wouldn't bypass that switch until I knew for sure what it does. If its only an upper pressure safety, in cold weather you are ok. If its a cycling switch, your compressor will run constantly. Thats bad.

Its a miata- put the top down and drive faster?

We never tried to fix the AC in our miata because.... you can put the top down.

CGLockRacer wrote: Also, does anyone have one of those switches (it's held in with 3 phillips screws) laying around?

I don't happen to have the switch "laying around", but I do have my '92 Smurf sitting in my buddy's weeds that's waiting to be parted-out. Don't have alot of spare time to pull it, but it's yours if you want it. In Bowling Green, OH, so reasonably close to you.

I should have one, I removed the A/C from my Miata so it should be around somewhere. I'm not as close (Ashland, OH) but it shouldn't cost too much to ship.

EDIT: If it is on the compressor then I don't have one...I scrapped all my spare compressors.

In reply to grafmiata:

Hmmm...what are you doing next Sunday?

In reply to EvanB:

It's mounted on the compressor :(

CGLockRacer wrote: In reply to grafmiata: Hmmm...what are you doing next Sunday?

No plans right now other than waking up at the crack of noon.

Grafmiata,

In reply to grafmiata:

I tried to PM you, but it got bounced. email me at Phil at PhilMatherRacing dot com and I'll contact you. Thanks!

If it doesn't work out with grafmiata and you're willing to pay shipping, I believe I have one sitting in the garage. Someone else may have scrapped it though.

CGLockRacer wrote: In reply to grafmiata: I tried to PM you, but it got bounced. email me ?at Phil at PhilMatherRacing dot com and I'll contact you. Thanks!

Just got kicked to Spam folder. Will email back in the a.m. when I get home from work. BTW, is this something we can get to from above?

In reply to grafmiata:

Yeah. Might need to loosen the alternator, but we can get to it from above.