Fuel Sender testing question

I hooked a trouble/test light up to the fuel sending lead (next to gas tank) on my 1967 Valiant and there was a light, but it slowly "pulsed" on and off. Is this normal?

I'm pretty sure the sending unit is shot, but I wanted make sure the pulsing light was normal. Maybe helped keep the gas gauge needle from bouncing all over the place?

Thanks ahead of time Mopar Dudes!

Yes that is normal.If you connect a wire to it that is grounded and key on the gauge should peg to full.Just dont leave it on very long.I just hook it up then turn the key on.Rocky

Also, before you pull the sender make sure it has a good
ground. Should have the strap from the fuel tube on the sender to
the fuel line on the body.

Thanks guys!!