Changed my water temp sending unit and still nothing on the gauge.

How about the other way around? What part number did you put in there?

A warning light sender is completely open (infinity resistance) when cold or normal operating temp, and closes to a dead short when overheated It is, in effect, a switch.


This is the part.

http://www.oreillyauto.com/site/c/detail/BWD0/WT127.oap?pt=01392&ppt=C0033