Bench Testing a Fuel Gauge with a Heathkit Decade Box

In this video I use a vintage Heathkit IN-37 Resistance Substitution Box (aka Decade Box)
to bench-test a 90 ohm GM fuel tank gauge.
You can use this same testing principle on any resistance based automotive gauge.
Heathkit sold similar boxes under the IN-12 and IN-3137 part numbers.

1980 Catalog:
https://archive.org/details/1980-heathkit-catalog-848-winter/page/58/mode/2up

1963 Catalog:
https://archive.org/details/TNM_Heathkit_catalog_1963_radio_and_related_produ_20180404_0082/page/n33/mode/2up

00:00 Overview of Decade Box
00:55 Setting up the Test
02:00 Doing the Test
02:43 History
03:10 Modern Alternatives
03:32 Potentiometer Test