mines the same...dual contact n/c relay running off the hobbs switch...one set of contacts for the coils the other for the injectors with a start override switch and big autometer warning light. With ignition on the relay and warning light are powered through the n/c contacts of the hobbs...after starting the contacts of the hobbs are opened and the circuit override switch is opened...when the pressure drops the contacts of the hobbs are closed powering the relay and opening the contacts feeding the coils and injectors.