Installation Guide
P. 7
Quenching Diodes
It was said earlier that a relay energizes itself by applying positive from the battery to either 85 or 86 and
grounding the other terminal. This is not absolutely true, some relays are “polarized” if they have a quenching/
suppression diode (A diode installed between the coil terminals 85 and 86, could be internal or external).
To activate the coil on this type of relay, make sure that the +12 volts trigger is on the same terminal of the
relay as the anode (+ or non striped side) side of the quenching/suppression diode, and that the negative
trigger is on the same terminal of the relay as the cathode (- or striped side) of the quenching/ suppression
diode.
When a relay’s coil is energized, a magnetic field is created and energy is stored in the coil. When power is
removed from the coil, the magnetic field collapses. This causes a reverse voltage to be generated and can
sometimes reach 200 volts. A quenching diode absorbs this reverse voltage spike.
A closer look at a relay
Now that you know what the main inscriptions are on the relay, take a look on the side, and you will see another
inscription: 12 VDC, 40/ 30 A.
12 VDC: This indicates the coil voltage rating. For an automotive relay, it's usually 12 volts DC.
40/ 30 A: This indicates the current carrying capability of the contacts 30, 87, & 87A.
40: Indicates that the normally closed circuit (30 and 87a) can safely handle a maximum of 40 amps of current.
30: Indicates that the normally open circuit (30 and 87) can safely handle a maximum of 30 amps of current.
Examples: The following examples demonstrate some of the most common uses for relays: isolation,
inversion, interruption, strengthening current, and for powering multiple wires from one source safely.
Example: Powering a second ignition
Powering multiple wires from one source safely
Problem: You need to power multiple ignition wires to remote start the vehicle, but your module only has one
ignition output available.
Solution: You will need to add a second ignition relay to power the second-ignition wire. (Jumping ignition 1
to ignition 2 is never recommended
Always use a relay. The vehicle circuits are isolated for a reason;
the wiring of the remote star module should reflect this.)
The Relay Connections
85: Connects in parallel to the ignition 1 output from the remote start module. This becomes the positive side of
the coil.
86: Connects to the Ground Out When Running wire from the remote start module. This becomes the
negative side of the coil.
87: Connected to a fused +12 volts source, that is capable of supplying power for the vehicle's second ignition
wire. This becomes the source of power for the 2
nd
ignition wire.
87A: NO CONNECTION. This terminal is not used in this application.
30: Connects to the vehicle's second ignition wire. This becomes the output of the 2
nd
ignition relay.
Comments: The relay is only energized when the vehicle is running by remote start. When started with the key,
the relay is not energized and the integrity of the stock system has been preserved.
Example: Isolating a parking light output
Isolation:
Problem: Some vehicle circuits need to be isolated from feedback. In some cases, when a vehicle is remote
started, feed back occurs on a circuit, and powers another device or switch, that was not intended to be
powered during the remote starts.
The following example will be a positive (+) park light circuit that feeds back and activates the windshield wipers
during remote starts.
Solution: When power is applied to the OEM parking light wire it back feeds through the park light switch, and
activates the wipers. Where the connection was made from the start module’s park light output, and the
vehicle's park light circuit, the OEM park light wire is cut to isolate the park light switch and the actual parking
lights. A relay is added to the park light circuit so that power from the remote start module is only sent to the
parking lights and not the parking light switch.