1987 Toyota Pickup A/C stumped.
 

Ok guys, totally stumped, searched, and need help so here goes nothing.

A/C not working, checked simple stuff first (fuses, relays, that circuit board thingy, leaks setting off low pressure switch) :bang::bang::bang:

The compressor comes on if I jump a wire to the battery, but the suction line does not get cold despite being full of freon and everything checking out. My main question is about the compressor and if it has just quit on me? Btw, the truck has been converted to r134 by a previous owner.

How do you know "its full of freon"? A gauge set will help you troubleshoot. Could be the compressor, could be the expansion valve. Have you tried jumpering the pressure switch to see if the clutch will engage?

Doing any type of AC work without manifold Gauges is like fishing without a hook on the line.

Then it could be a over pressure problem from being over full .

just how do you know it is full??

and the hook doesn't even cost much. http://www.harborfreight.com/a-c-man...set-92649.html

I'll say. You don't know anyone with any gauges. I can name 20 people that have them and my church has 6 sets. That said my AC is read 40 on low 300 on high

I'll pick up a set of gauges within the next couple days and post back. What readings on the gauges mean I need a new compressor? No high side pressure?

[QUOTE=stock87yota;52281652The compressor comes on if I jump a wire to the battery, but the suction line does not get cold despite being full of freon and everything checking out.[/QUOTE]

Does compressor come on when you turn the AC on BY normal means? Meaning Fan on, AC button depressed.

The FSM should have those figures... Or you can search this forum.

The gauge readings will vary with the ambient temperature, but as a general rule the low side should be around 35 and the high side about 250/275

Ordered a set of gauges online and waiting for them to arrive, but it may be a week before I can get to it. However, I was under the hood today and noticed the clutch on the compressor slowly turning intermittently with and without the A/C button depressed. Does this mean anything specifically?

And the compressor does not come on with the button depressed, just when I jump the low pressure switch, but the suction line does not get cold. I also apologize for jumping the gun and troubleshooting without gauges.

I would only jumper that low pressure switch long enough to confirm the clutch works. There is a reason its there. You could damage the compressor. The pulley turning occasionally, could be bent a little and catching.

If jumping low pressure switch engages the clutch then you are low on freon orrr the switch is bad.....

Most likely you have a leak and need to repair it.

The fact that the compressor clutch is slowly turning without the clutch officially engaged means one of two things
1) The clutch is dragging more than it should, or
2) the compressor is really easy to turn because
a) you're out of freon and there's nothing to compress, making the compressor turn easily, or
b) the shaft is sheared off inside making the clutch turn freely

First thing is to ascertain you actually have freon in the system. Sounds like maybe you don't.

I would put my hand on the front of the compressor (engine off) and try to turn it. If you can turn it by hand, something is very wrong. Even if it was completely out of freon (refrigerant), it's at least pumping air through very small pipe, and should have plenty of resistance.

The clutch turns VERY easily with the engine off. Even with freon, would a low pressure switch detect low pressure if the compressor isn't functioning? Thus prevent the clutch from engaging?

have you put a set of gauges on it yet? you need to put gauges on, and jump out the low pressure switch. your gauge should have a saturation temp on it. low side temp should be 45ish and high side should be 30ish over ambient. if the low side drops below 45, you are more than likely out/low on charge. excuse my ignorance/laziness, but do these have TXV/receiver, or fixed orifice/accumulator? you will need to charge to subcooling if TXV and superheat if fixed orifice.

Mine has the expansion valve and receiver/dryer.

You should be able to turn the clutch by hand, that's normal. It should give a little bit of resistance but not a lot.