Does the air conditioning compressor clutch get its voltage through the engine compartment fuse box relay labeled Fan No. 1? Also, if I jump the pressure switch, should I see 12 volts coming through the wire at the compressor clutch?

 

Exact wiring would depend on year.

The clutch receives power from the magnet clutch relay. The relay solenoid and clutch plus other AC circuits receive power from the AC fuse.

The AC amplifier turns the clutch relay on/off.

The pressure switch location in wiring can be between the AC fuse and and clutch solenoid.

If you jump the switch you may see 12V at AC solenoid but the AC amplifier would still need to activate the AC solenoid (complete circuit to turn relay on) for there to be 12V at the clutch.

 

Thanks Toyomoho, the Camry is a 1986 Camry LE. I did replace the 10 amp AC fuse located behind passenger side kick panel.
With the meter set to ohm, I found continuity from the wire leading to the compressor clutch to a similar colored coded wire entering the engine bay fuse box.
I have seen the A/C amplifier pictured under the dash by the passenger side.

Where is the A/C relay solenoid?

I'm trying to figure out if the compressor clutch still works, then if the compressor is still viable (I've been able to turn it a little with my fingers, it's a pretty tight space).

 

You can determine if the clutch works by applying 12V DC to the clutch wire at the clutch. You will need to connect the negative power wire to chassis.

Take caution as the AC compressor most likely has a speed sensor (RPM sensor) built into the compressor housing. There may be more the one wire at the compressor location. Wire colors for the senor may be white/yellow and white/red.

You want the wire going to the clutch (there is only one wire to the clutch which maybe black/white). The other side of the clutch wiring is grounded via its body to the chassis to complete circuit.

The AC relay would be in one of the relay/fuse boxes inside the engine compartment on left side.

 

Toyomoho thanks,
I was able to activate the clutch. Its at least good to know that works after 5 or more years of not working. I have a single gauge and the pressure in the system is not measurable. So I guess its starting from scratch and I need to determine leaks etc.

 

A typical leak location is the compressor drive shaft seal. On rare occasion the condenser on the front of radiator is damaged from a stone, etc and leaks.

You can install Freon having a UV dye.

However if the system has been out of Freon for years air may have entered and vacuuming required to remove the air plus replacement of the drier would be a good idea. In addition to finding any leaks.

 

Thanks Toyomoho,
I just watched a video of Erikthecarguy on youtube as he applied the vacuum to the ac to look for leaks. Complicating my job is that I will be converting it to r134a from r12. After doing a vacuum check on the system, and probably I'll find it doesn't hold vacuum, I wonder if it would do much harm at all if I used a little r134a (with the dye) to detect the leak.

I've done a bit of research and see that some recommend a flushing of the system (not compressor) but also to drain the compressor and refill with ester oil as this has been said to be compatible with both refridgerants, and the replacement of the drier is standard. O rings....and a r134a pressure switch.

I've also read that some have had success with just charging with r134a, and others say that may work now, but it will screw up the system the next time you try to vacuum it. hmmm

 

Lots of opinions out there.

Suggest reviewing pre-R134a posts at the Toyotanation.com website for suggestions on Toyota vehicles.

You can still buy real R12 at sites like Ebay.

Supposedly mineral oil and R134A don't mix. The system still has mineral oil in the tubes, etc.

Since the system has no freon might remove and drain the compressor then flush out the old oil with ester oil. Make sure you get all oil out before adding the appropriate quantity. And replace the seal on the drive shaft which can fail.

Then replace the dryer with one designed for R134a plus use the green o-rings. The dryer needs to be replaced anyway if the system has been out of Freon for any length of time.

If flushing might back flush in the opposite direction otherwise take out the expansion valve.