'04 Tahoe 4wd switch testing/water pump gaskets

[JustGibby]

We've got an '04 Tahoe. Apparently, it has decided that it doesn't get enough attention, and has proceeded to go all to hell on me. So I have multiple unrelated issues I'm trying to figure out/fix at the moment. Well, I'm fairly certain they're unrelated. Anyhow, I've got a couple of questions I hoped y'all could help me with.
1. Installing a new water pump and thermostat. Every single thing I've read or seen online talks about or shows a paper/rubber-like combination gasket or a metal gasket for the water pump. For some reason, my water pump gaskets are ONLY paper. Should I use these or order different ones? If I use these, should I use any type of RTV or anything with them?
2. Trying to test the resistance of the 4wd push-button selector switch. I've got a multimeter and a list of specs. I know about the ohms, kohms, etc. But I don't know how to test this thing. Where do I put my probes (or whatever they're called)? How do I test each individual button?

 

[Fless]

2. Trying to test the resistance of the 4wd push-button selector switch. I've got a multimeter and a list of specs. I know about the ohms, kohms, etc. But I don't know how to test this thing. Where do I put my probes (or whatever they're called)? How do I test each individual button?

See this link for a video.

“Service 4WD” message

2004 Tahoe Z71 w/ about 155,000 miles. I did a little digging on this forum and found a couple threads on this issue, but still had some questions. Today I got a “Service 4WD” message on my cluster display and also noticed the lights indicating 2wd, 4hi, and 4lo were not lit up. I use 4WD...

www.tahoeyukonforum.com

EDIT: also see these articles but note that our systems have a 5v ref, not 8v:

https://atracom.blob.core.windows.net/gears/2006/2006-07/2006_07_10.pdf

This one has the switch ohm values:

https://atracom.blob.core.windows.net/gears/2006/2006-08/2006_08_08.pdf

 

[JustGibby]

That's the exact post I got my list of specs from! I hadn't tried to watch the video before though. A lot simpler than I was expecting. Thanks a bunch for that. Still looking for opinions on the water gasket...

 

[PPV_2018]

Your truck should take steel gaskets for the pump and a paper gasket and o ring for the thermostat. If you don’t have the steel gaskets you need them . . Or you’ll definitely be doing the job again sooner than later.

Use some silicon rtv with the correct gaskets.

 

[Fless]

That's the exact post I got my list of specs from! I hadn't tried to watch the video before though. A lot simpler than I was expecting. Thanks a bunch for that. Still looking for opinions on the water gasket...

The switches are easy enough to disassemble and clean the contacts, so if your resistance measurements don't pass muster, consider doing that. (Note that in the video he mis-states one of the resistance ranges.)