First, the VOV replaces a fixed orifice tube and does not work in a thermal expansion valve system.

You didn't list a model, so...

If you have a 240, it WON'T work unless the 240 is one of the following:

1991
1992
1993

For 240 models, there is one location: In the pipe between condenser and evaporator. Keep in mind that in 1991-1993, the accumulator is not a high side fitting; that is the low side of the system and everything from the orifice tube back to the compressor is all low side.

The 240 orifice tube (91-93 only) is located in a joint in the high side pipe, about 1/2way back on the right side frame rail inside the engine compartment. That is the small line.

Again, if you have a 240 made before model year 1991, forget about it.

For 700 models:

If you are driving a 700/900, there are two places for the VOV to be installed (depending on model year), and they only differ in the sense that they are in DIFFERENT PLACES of the same pipe. I think that they went from evaporator placement to expansion pipe placement in 1991. It's still the same pipe -- goes directly from condenser to evaporator on all models.

The earlier location is in the joint where the liquid line (small pipe) enters the evaporator. The later location is in a joint in THE SAME PIPE (small pipe) where the transmission cooler lines pass the right side frame rail. it's a little union and the pipe gets bigger on the rear side of the joint (this is the expansion pipe). You literally can't miss it if you're careful.

--
Chris Herbst, near Chicago.