A 12v test light will work fine.
There seems to be several different kinds of pressure senders.. At least two for the "guage style" switch itself.

As mentioned above, grounding the connection directly is a bad idea. Grounding through a test light is ok as it limits current.

The aftermarket senders I've bought aren't the pulse type, they seem to be pressure/impedance related.. My factory guage doesn't quite work right either.

22REturbo.net




1988 4Runner
22RTE core, turbocharged, megasquirted...