06 tach doesn't work, a few of us have been down this route. If you check past postings you'll see, bottom line is ultimately you'll have to replace the whole cluster and as the cluster has small computer in it you'll have to have done at the dealer's as the computers have to be programed for correct milage etc. otherwise truck won't run. That's the route we finally wound up going. Not a cheap fix as dealer keeps the truck for a couple of days while they send in and get milage corrected with company and so it goes. It was around a $500. 00 dollar fix. Didn't make sense to us to put in used cluster and than have to go through the dealer process and than have the used cluster go caput.