A couple of junk yards in my area have trucks with complete power steering systems that I want to install on my truck. One set has a switch or something screwed on top of the pump with two vacuum lines coming out of it. The other dosen't. What's the switch for? The set without the switch is a lot cheaper, so I want to get this one. I just want to know if I need this switch or not. Both trucks were fuel injected. Mine is a 94 4x4, 22re.

That is the Vacuum Switching Valve (VSV) for the idle-up valve atop the 22RE intake (if present). That idle up valve is used for p/s and A/C, if you have neither, then you may not have the idle-up VSV. Makes no difference in the pump operation, you can leave the VSV disconnected from the intake if you want.

It is sort of a useless feature, my '85 had one of those vacuum lines plugged with intake goo, I cleaned it out and I don't think I ever noticed that the idle ever bumped up when I turned the steering wheel. My new pump has no such switch and it works fine. If the steering needs some help at idle, a blip of the gas pedal is usually all you need to boost the fluid pressure.

Thanks for the reply. Looks like I'll go after the one without the VSV and save a few bucks!