Temp guage doesn't read while one

[THOMASO1371]

I have 90' Silverado with the moonie guages. I recently installed a little under seat self powered subwoofer, everything was fine on test drive. Went out today my temp guage never moved. When I turn the truck off it moves to normal operating temp.

Any ideas on if this is a guage issue, sensor issue, or maybe I screwed something up installing the sub?

Showing pics with truck off, then when I turn ignition to acc position.

 

[PlayingWithTBI]

It could be your gauge but, I'd check the connector and sensor between cylinders 1 & 3 exhaust ports on the head first.

 

[THOMASO1371]

It was that. I checked the one up top, didn't realize there was a second. Was also messing me spark plugs and must have disconnected it.

Thanks for the help!