CAR ALARM AND REMOTE START INSTALLATION GUIDE
Copyrght 2002-2004 Triple S Customs 33
3 parts make up a standard relay. They are known as the COIL, CONTACTS, and the SPRING.
COIL:
• This is the part of the switch that allows the relay to be controlled electronically instead of by someone
pressing a button or flipping a switch. The coil of a relay is made up of many turns of small gauge wire
wrapped around an iron core. When the coil is energized it creates a magnetic field.
• Pins 85 and 86 make up the terminals of the coil. When 12V is connected to pin 86 and ground is connected
to pin 85, the coil is activated.
NOTE: Usually, it doesn’t matter whether pin 85 or 86 is used for 12V or ground. But if the relay has an
INTERNAL SPIKE SUPPRESSION DIODE, 85 must be the negative terminal and 86 must be the positive
terminal. Most OEM vehicle relays are wired this way and it is a good habit of always using 85 for the negative
terminal and 86 for the positive terminal.
CONTACTS:
These are the terminals that connect into the vehicle’s electrical system. Functions include turning a vehicle on/off
or disabling it, changing a wire’s polarity, or increasing the current. Depending on if the coil is energized or not,
pin 30 will be connected to either pin 87 or pin 87A.
SPRING:
This is the part of the relay that keeps the common (pin 30) and the normally closed contact (pin 87a) connected
while the coil is not energized. Magnetic force created by the energized coil will connect the common (pin 30) to
the normally open contact (pin 87)
A
A
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This is a schematic of a relay. A similar schematic is printed on the side of most relays.
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