Need electrical help! Tach does not work consistently & the volt gauge started to bounce. Cleaning all wire contacts and looking inside dash - I found an unknown part on my LARSON 5.7L 1993 - I have a Thunderbolt IV (4barrel-CARB) & this is not shown on wiring diagram: PART: Kasor/Medallion # 1039-07654-04 - see attachment for photo - with Ignition Key on - I checked the voltage on the purple wire on the RPM Gauge to ground - checked OK. I tested the gray wire from ignition coil to the tach and it checks OK. Voltage at battery 13.82v. Voltage at Gauges = 13.12v. The voltage stops at the KYSOR module but has voltage at the KYSOR 4-pin connector. Looking to the internet - KYSOR & Medallion merged then became another company - now back to Medallion Instruments. What is this part, what does it do, can I test it? And where might I find a replacement or Retrofit with instructions?
