So in a last effort to get a working stock tach in my car, I'm converting it from the S5 cluster I had (looked like sh*t), to a extra S4 one I had from a old parts car (known working).

From what I've looked up, the S5 automatic clusters have 3 plugs for the back of the cluster, whereas the s4 only has 2. I've tried looking it up in the FSM, but for the S5, they only give wire colors, not any actual pin-outs. I've been able to match up a lot of them but I'm still stuck on some things.

1. Is the "Shift Up" indicator powered by the ecu? My car is carbureted so the ecu, along with 3/4 of the wires have been removed from the car.

2. When I turn my key to the on position, the clusters (with the pin moved to the correct location on the plug) water temperature gauge spikes all the way up before I even crank over the car. My aftermarket gauge which is spliced out of the same wire shows a regular temp (100 or so after sitting in the driveway not being started all day).

3. Sometimes, when I turn the key to the on position, the gauges will work, but after I crank the car with the starter and let it come back to the on position, the cluster shuts off. The lights in it go out and all the needles drop. Any ideas?