lighting / switch help

[reefguy89]

i have a set of hella 500's and i upgraded to 100w bulbs. I am using 12g wire and a 30a relay but i keep blowing fuses. So i am going to do is pull out the relay and wire directly to a switch. The 2 lights will draw a max of 17amps. So can i use a 20amp switch or should i use a 30amp switch? Where can a get nice looking switches?

 

[Marx]

what size fuse are you running?
12awg can only handle 20a you need 10awg and run a 30a fuse

 

[reefguy89]

what size fuse are you running?
12awg can only handle 20a you need 10awg and run a 30a fuse

it keeps blowing the 30a fuse but the fuse size shouldnt cause it to blow. its only 2 100w bulbs so max amps should be 17. i have 2 inline fuses one 20 and one 30 at the battery. also can i run the ground on the fire wall.
heres a funky drawing of the layout

 

[Marx]

it keeps blowing the 30a fuse but the fuse size shouldnt cause it to blow. its only 2 100w bulbs so max amps should be 17. i have 2 inline fuses one 20 and one 30 at the battery. also can i run the ground on the fire wall

Sounds like you have a short happening, make sure there are no nicks in your wires, that setup should run your lights

 

[reefguy89]

coming off the coil on the relay i hooked it with the ground from the switch and grounded them to the fire wall is that ok.

 

[Marx]

Hooking the negatives (grounds) to the battery would be ideal

 

[reefguy89]

Hooking the negatives (grounds) to the battery would be ideal

i thought the shorter the run the better.

 

[Marx]

Its not long enough to make a difference, there is something causing the circuit to pull more than 30A, by running dictated lines you reduce the interference, or make sure your grounds are connected to bare metal

 

[reefguy89]

would it be better to get a bigger switch that can handle the load and wire it up straight instead of using a relay.

 

[Marx]

Not really

 

[Redtruck-VA]

it keeps blowing the 30a fuse but the fuse size shouldnt cause it to blow. its only 2 100w bulbs so max amps should be 17. i have 2 inline fuses one 20 and one 30 at the battery. also can i run the ground on the fire wall.
heres a funky drawing of the layout

Looks like you are doubled fused on the lamp side. The switch side, coil of the relay needs the 20A fuse inline with it. The 30A fuse should be right off the battery going to the relay. From he relay to the light doesn't need a fuse. Run the ground to the firewall or battery.

 

[Redtruck-VA]

it keeps blowing the 30a fuse but the fuse size shouldnt cause it to blow. its only 2 100w bulbs so max amps should be 17. i have 2 inline fuses one 20 and one 30 at the battery. also can i run the ground on the fire wall.
heres a funky drawing of the layout

Looks like you are doubled fused on the lamp side. The "switch side", coil of the relay needs the 20A fuse inline with it.
The 30A fuse should be right off the battery going to the relay. From the relay to the light doesn't need another fuse. Run the ground to the firewall or battery. Your problem is the switch on the light side, it should be inline with the coil. Turning the switch on allows current to flow through the coil, causing the contacts to close for current to then flow from the battery to the lights ..

 

[reefguy89]

o yeah i got it figured out. i feel like a ******* i wire the switch wrong and it was causeing it to short out. i will have pics up later of the finished product.

 

[Redtruck-VA]

Stand alone stuff is easy to wire up using relays, it's when you start messing with the factory stuff that it gets challenging as the switches using 5vdc actually terminate various resistances to ground telling the FCM/PCM to turn on or off the different lights. Which leads to the possibility of changing the resistance in the multi-function switch to run both hi/lo beam lights at the same time, which is something I'm interested in doing.