First, it sounds like you had a bad t-stat. With it out, you most likely will not get good heat, so like you said, it will need replaced. As far as the gauges, if the check engine light is on, have the computer scanned at a nationally recognized parts store. Most will do it for free, and it may direct us. The gauges could be from a ground problem, so in addition to the neg batt terminal, look for damaged or broken ground straps. If nothing is found, you may need to have the body control module tested.
Let me know if you have other questions.
Sunday, March 15th, 2009 AT 3:06 PM