My 1996 ford ranger AC compressor will not run. I put 12 v straight to it and it ran. What could be the problem?

sounds more like a temp door is stuck feel the larger pipe for the ac while it is running if its cold you have a door problem

sounds like fuel pump in tank is not working. Can you hear it hum when you turn key to ON?

It should hum for 5 seconds and build up 40 psi of fuel pressure.

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It could be the fuse, climate control, switch, or relay.
If you check at the switch, that will also tell you if the fuse might be bad.
Then if you check at the relay, that will tell you if the climate control is bad.

My AC quit all of a sudden and it was a switch in the ac line. It was located on one of the air conditioner lines almost next to the firewall. Looked like a little box. When the p/u was running and the ac was turned on, I tapped it with a screwdriver handle and the ac compressor came on. I think it was a low pressure switch and is supposed to keep the ac from running without any freon, so you might try that. Best of luck.<!-- from fixya rte -->

It's just low on freon, low pressure switch will cut a/c compr off and on, so it won't get damage a/c compr. due to low on freon, recharge it you'll be fine.

There is a low side pressure switch on the dryer,remove the plug in connector and use a wire to connect the two circuits together on the plug,if the ac compressor runs,and the ac cools fine,replace this switch,it just unscrews,and you will not loose any freon.

on the central fuse box inside the vehicle there are fuses 12, 10, and 2
on the under hood fuse relay box 7,17,25,16.
check those and report back.

Have you charged the ac. If so check the low limit sw. on the dryer it will cut the power to the compressor if the charge is low or if the sw. fails.

idle air control is ran by the power of motor cause the compressor is attached to motor for the compressor you need an idle air control module for a/c compressor this should bring life back to your a/c