Splicing temp gauge to temp sending unit

[fredbmxer4life]

I installed my digital water temp gauge yesterday and i was rushing and didnt have time to come home and get online to check out which wire to splice into so i took a wild guess and i ran it into the yellow wire coming directly from the sending unit (it is on a 2000 3.8 firebird). Now my problem is my the new digital gauge works great but now my gauge on my cluster doesnt budge and my car was idling high at one point like it was getting a low temp so pcm was tryin to warm it up. I thought maybe when i spliced it i only hooked up the yellow to one side of the splice (coming from sender) and the gauge to the other and the yellow side running to the motor didnt find its way to connectivity so i disconnected the wires and it threw the pcm through loop, i could hear it in the motor, so i know it was hooked up fine. I chose the yellow wire because the other was brown i figured it to be ground coming from the sending unit. Any idea on the correct place to attach the wire for the gauge maybe somewhere coming from the pcm in the wire cluster? I just want it to run off the stock gauge temp.

Thanks in advance