so after the track last weekend my oil pressure guage died. it shows below 0 (as if it shows when the car is parked). its an autometer and its under warranty but i dont realy want to send it back until i figure out if its my sending unit of the guage itself. so, the big question is...how can i check for signal. i mean, how many volts should it see if the car is running? i know my power and ground work because i tested them with a light. i ran a wire straight from the sending unit to the guage and still nothing. so i just went out and bought a multimeter but i dont really know how to use it. fill me in

 

Test lights are useless. I can't believe people still use them.

Sure, the light lit up. But how many volts does it take for that light to light up? Answer: You don't know. Test HOW MANY volts you are getting before the load, and how many you are getting after the load. You should have battery voltage before the load, and NO voltage after.