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6
Starter Interruption
The FM 3617i/FM 3717i/FM 3817i
requires an external relay for the interruption of the vehicle’s
starter circuit. The relay required should be adequately rated for the purpose intended. Please
note that a 30A or 40A (contact rating) relay should be selected. A standard 5 PIN automotive
relay manufactured by a reputable supplier (e.g. Bosch) would be adequate. The correct relay
operating voltage is required for the relay not to be damaged. 24V relays will not function
correctly in 12V applications and 12V relays will be damaged when used at 24V.
To connect the relay it only needs to be plugged into the relay socket on the FM300 Main
Harness. The two 2mm diameter black wires represent the two sides of the relay contacts
that are controlled via the driver ID Plug. Cut the wires as short as possible where higher
current will be interrupted via the relay.
Also use a cable tie to secure the relay through the mounting ear (5mm hole) to the main harness, or where
possible an M5 lock-nut and bold is to be used to secure the relay to the vehicle. Ensure that the relay wires
have enough play on them not to strain the relay terminal crimps connecting the relay to the wires.
It is not necessary to use a relay with a build in protective diode, because the FM 3617i/FM 3717i/FM 3817i
has built in protection already.
WARNING: Should a relay with a diode be inserted incorrectly, it will short
positive to ground.
See simplified connection diagram below: