power supply 12 volts this terminal is hot at all times regardless
of the ignition keys position.
is live 12 volts whenever the ignition switch is in the park , run
or crank position.
volt supply with the ignition in the run or crank position.
is 12 volt power when the switch is in the run position only.
is 12v in the crank position only mainly to energize the starter
Now on relays
you may find some other numbers. These numbers are the same on most
relays but there are a few exceptions. You may also find numbers
not mentioned here. I'm only listing the numbers that are most common.
is the positive power going to the component being controlled by
is the same as 87 except is for a second component the same relay
may be powering
volt positive to activate relay
is a ground for the activation coil of the relay.
also is a ground for the activation coil of the relay.
speed signal in the form of a square wave.
volt signal from terminal 50 engine cranking