How can i check the start contactors for 28v and ground on the coil?





These  two small studs are the wires for the field colapse diode across the coil.


The diode here below the wires.  It is not significant to your troubleshooting, but the studs are.




You can attach the leads of your troubleshooting light to the studs, and you are  watching the coil voltage.1475261301323-2088363355