Hey Del, Look what I found!!! An original Miller Gauge tester!!!

I used to have one of the Miller testers, but it disappeared years ago. Now I use a resistor substitution (decade) box instead. You just flip switches until it adds up to the resistance you want. It's not limited to certain gauges and it can substitute for any sensor even mass airflow. This Elenco brand costs less than $30 and works great.