JK-Ford

Yes you need a fuse between the relay and the battery. And you need a fuse between the switch and the fuse box. These fuses need to be rated large enough so they will not blow by simply using your lights. But small enough to protect tthe wires and relays in the circuit. Basicaly, every time you tap into power, you need a fuse. You need to place the fuse as close to the tap as possible.

matt852

Ok, I see, so what rating fuses should I look for? So I understand there need to be a fuse from the Battery to the Relay, I have an 40 amp relay, one from the switch to the cig lighter, I think I'll just go with using the cig lighter. Does there need to be one from the lights to the relay?

Thank You for your help

JK-Ford

Use this formula: ________ (total watts of lamps) devided by 12 volts = Amps

No. Just the one above will do fine.