Gunpilot

Had to buy an after market pigtail for my ford compressor. Wire colors are off. Can't find schematic that shows which is pos and which is neg. almost stopped a 5.0 today to ask if I can use my multimeter real quick on his car. LOL!

Can anyone help me out. This is last connection of AC I need.

Thanks.

tbone heller

It is just an electo-magnet. Ground one wire of the pigtail & apply 12v to the other for the clutch to engage. If it does not engage, swap wires & retest.

MRM331

While you're at it, also run the 12 volt side to a relay to kick your fans on and a vacuum switch (Miata or Ford purge canister valve works). Route a vacuum line to the valve from your manifold and leave the other side open (or attach to a small breather filter). This will create a small, intentional "vacuum leak" whenever you turn on your ac which will in turn bump the idle up about 200 rpms.

-Jason

Gunpilot

I ended up doing as we discussed on email. I tied the following 3 wires together:

1- from button to ECU
2- from ECU to fan relay
3- from ECU to compressor relay

Now when I push AC button in the car it sends 12v to fan relay and compressor relay bypassing where the Miata ECU would have been. I will now ad the Miata purge relay into that tie in making 4 wires at that point.

Thanks for the tip

MRM331

I actually picked up that intential vacuum leak idea when I started looking in to the MegaSquirt stuff. Since the MS1 and MS2 don't control AC that's what they do.

-Jason

fun02se

Good thread, answers my questions!
Thanks guys!