I've got an 89' Silverado 1500 5.7. Just replaced the ignition coil, after reconnecting the battery and driving the truck noticed that the temperature gauge wasn't working and was working before changing the coil. Truck was missing out before replacing coil, truck runs better now with new coil but no temp gauge. Wondering what my problem is??

 

Make sure you didn't unplug the temp. sensor.

 

Checked temp sensor and it is plugged in but ground wire seems corroded and frayed???

 

if it is corroded and frayed than it may have a bad connection put a new end on it and see if that helps