Ok, with regards to the TACH issues I have a 2006 dodge ram, just bought it and I had the problem that many of you have. And paying over $100.00 closer to 200 is total crap for a 10 min fix. So here is the fix that worked for me.

1.) remove the gage cluster from the vehicle
2.) remove the screws on the back side of the cluster staring with the screws on the tach side. You will notice the circuit board will flex up about a 1/16 to 1/8 of an inch as you continue to remove the screws working from the tach side across.
3.) there are a number of IC's you should now see when you remove the black plastic cover.
4.) if you divide the cluster in half and focus on the Tach Side there is four large IC's (talking very basic so everyone can understand). One that has leads comming out of all four sides and three that only have leads comming out of the two long sides.
5.) now this will test your skills at soldering. you need to apply flux (a Flux pen works good)to leads of the IC's and reflow (resolder) all the leads.
6.) When you put it back together I suggest to shim the board on the Tach side so the screws do not pull down on the board when you tighten down the screws.

And a link to his pictures
http://www.keepandshare.com/doc/3998...m-2-8-meg?da=y