testing

Does anyone on here have any expertise on the 80s vintage electronic dash units. Maybe someone with any type of schematic? I have a bunch I bought cheap from someone who wanted them gone and I know the 5 4312654 ones (1984-87 G body) all need the push button switches replaced. The other 5 are...

First, is there a definitive way to test these other than by substitution? Second, assuming one or both of the pair in a turbo distributor are bad recommendations on a good source (I don't really expect FCA to have these for over 25 year old cars) in the past I could just pick one up at the...

I have a potential customer who approached me today (referral from another) She has a 2005 Ram 2500 Quad Cab with the Cummins Diesel. Hers has single zone controls. My questions (to start out) the parts list shows two units, one is designated HAA the other HAD. I believe I deciphered it enough...