2017 86 tach signal
 

I'm trying to get a Healtech shift light to work, and followed the thread from q335r49 that was posted back in 2019. I tapped into the red and yellow wire at A36, pin 10, and the Healtech app showed RPMs, for about ten seconds. The signal came back a few times for a few seconds, but then goes away. I've checked the connections and they seem to be good with little resistance. Any info is greatly appreciated.