Welcome! Here's my take on your questions:

1) Take the switch out of the dash, disconnect the wire harness (caution: live 12V -- just be aware). Carefully disassemble the switch, take an emery board to the contacts (they'll be corroded, and that's why they only work one way). Carefully reassemble the switch, plug the harness back in, verify switch works in both directions, re-insert in dashboard.
2) Turn signal relay is dying. You can use a generic one from the auto parts store and it works just as well. Make sure to get one with the same prong pattern, then zip-tie it or whatever to the driver-side kick panel.
3) I suspect it's either the switch or more likely the resistor. The factory service manual (can be found on the handy russian site mentioned several places on this board) has a troubleshooting procedure for the switch, and instructions for pulling the resistor. Resistors can be bought from NAPA or the like for ~$30, and takes about 1/2 hour to replace.
4) Well, I've never actually used mine since the pump is el bustido, but I believe you pull the column switch for the wipers towards you? Someone else chime in here.
Engine:
1) Sounds about right. These gauges are notoriously innacurate -- I think the general concensus is that as long as you see the needle move to the right when accelerating that's about as good as it gets. Lots of folks have replaced it with mechanical gauges. Your sender unit may also be on its way out, and that's a pretty simple replacement too -- it's down by the oil filter.
2) No idea here. Anyone else?
3)Uhm... somewheres around 3000 rpm I think.

Things to watch out for: There was a recall on the crank bolt -- you should make sure you have the new one or replace it next time you do the timing belt. Capacitors going bad in the ECU. Strong fishy smell and/or rapid clicking from underneath the glove box. This can be visually inspected by pulling the ECU out of the case and looking for corrosion. Several web pages with pictures exist. The IAC (idle air controller) can give your idle fits when it starts to go. There's a place selling brand new IAC motors at very reasonable prices -- I've got it bookmarked if you need it. Idler arm/pitman arm wear. Make sure your fan clutch is in good working order -- these engines aren't too forgiving of an overheat condition and the heads will warp easily. Valve guide seals (smoking on startup?) and possible dropped valve guides.

All in all, though these are strong little trucks, and respond well to TLC.

Good luck with yours!

Eric W.

PS -- It's a good idea to add your vehicle info to your signature so that when you post with other questions it's obvious to us all what type of motor/transmission/SWB/LWB etc. you have! <img src="/forums/images/graemlins/kewl.gif" alt="" />