[lew20vt]

pins 27 and 37 on the aan ECU need switched power. Pin 18 needs full time power. Pin 15 is not used. Pin 40 from the aan ECU is the tach signal to the cluster. The temp gauge does not get signal from the ecu it gets signal directly from the MFTS on the aan water manifold. Put some power to pin 18 and you should get something. I think you're close.

 

[lew20vt]

Didn't I try to go down this road with you in April? Pin 40 from the AAN ecu which is a violet and black wire is the output signal to the tach in the cluster. You need to find the tach input signal wire in your 90 wiring diagram and connect the two together. I don't have a 90 wiring diagram to tell you which wires on that is on the cluster. Get a wiring diagram. Neither of these issues should prevent your car from starting.