vacuum leak or bad pump question

[JohnMQ]

I seem to have an problem with 4X4 and vent air routing. I thought there was a vacuum leak but.... This is what I have done so far. Checked auto-locking hubs and hoses with no air leaks. Disconnected hoses from relay at the battery and plugged. Vacuum Pump still runs continuously. Disconnected hose to vent system and plugged. Pump runs continuously. The vacuum developed by the pump seems low but i don't have a gauge is see what it draws. I held my finger over it and released. Not any noticeable change in vacuum and pump runs continuously. I think I either have a leak in that black canister that the pump connects to (did check out hose from pump to canister and good), or the pump is bad.

5 questions:
1. Is the vacuum pump suppose to run continuously?
2. If it is suppose to cut off where does it get it's signal from (PCM)?
3. Am I on the right track?
4. I have to send my wife to get a replacement part - anyone know what the part number is for both the pump and canister? Without a part number she would ask for that "thing-a-ma-jig" my husband wants and the parts manager would give her that "deer in the headlight" look. I will take a pictures of it for her to take.
5. How do you get the pump off?

Thanks Guys.

[Big Calo]

Sounds like your on the right track. You might move this to the 99-03 section as there is a little more traffic over there. I only post here if it is a early 99 specific question.

[JohnMQ]

Originally Posted by Big Calo

Sounds like your on the right track. You might move this to the 99-03 section as there is a little more traffic over there. I only post here if it is a early 99 specific question.

Well the truck is an early 99. very early. I would move it but don't know how. Sorry.\ and thanks