Help wiring 7" kragens - fuse keeps blowing

So please share with me what was the mistake you had made?

 

I give up for today....maybe I'll try again tomorrow.

 

Yeah I'm in Az. I'm not sure where Sierra Expeditions is, probably Phoenix correct?

 

My collection of blown fuses just from today trying to get those fucking lights working. 2 trips to autozone and about $20 worth of fuses.....

 

I think you might be right. I couldn't quite read the writing on the diagram.

But after you point it out it does look like that.

 

Tried that and it still didnt work, lights would not power on.

 

Go directly to the battery the fuse isnt enough for a hid offroad light let alone 2 of em. use an inline fuse so you dont blow the light

 

hids draw less power...so no...im using 1 25a fuse to the relay the another 25a fuse for the switch

 

Please tell me that everything connected to those fuses is 10ga or larger wire and that the switch is rated to 30a or more!

 

well im using a relay so theres no need for a 30a switch....and yes using 10g and 12g wire for everything off the battery.....most people use a 14g from the battery and are fine.... there is no high power going into the cab, i used a 25a auro fuse because people say that you cant use anything lower off the battery

 

Electical 101:

Lesson 1:
Continuous load shall be no more than 80% of the rating of the fuse.
Rating of the fuse shall be no more than 80% of the rating of the conductors, switches, relays... anything in the circuit.

Calculations... Large to small, multiply by 0.8. Small to large, divide by 0.8
Example: Lights draw 10a. 10/0.8=12.5... fuse needs to be 12.5 or larger.
You can't find a 12.5a fuse, so you use a 15a fuse.
15/0.8=18.75a. All conductors, switches, and relay contacts must be 18.75a or greater.


Lesson 2:
The purpose of the fuse is to protect the wiring and the vehicle.
You can connect a 1-amp fuse to ANY power source... battery, wall outlet, flashlight battery.
You can connect a larger fuse to any power source.
Refer back to lesson-1 for proper sizing of components beyond the fuse.
The fuse should be installed as close to the battery as practical.


Okay... Fog light specifics.

You need the large fuse and conductors only on the lamp supply line.
That section of the circuit runs from the battery through the primary fuse, to pin 30 on the relay, out pin 87 on the relay, and to the lights.

The pin 85/86 side of the relay does not require a lot of current. You can use 18ga wire and a 5a fuse on that portion of the circuit.
So...
Battery (or underdash fuse box) to 5a fuse to switch to pin 85 on the relay.
Pin 86 on the relay is grounded.

Larger fuses don't give you more power... they ALLOW you to draw more from your source... but a 25a fuse running through 14ga wire and a 10a switch means that the wire and the switch are your fuse.
You can connect a 1a fuse directly to the battery to power a low-draw system.


"i used a 25a auro fuse because people say that you cant use anything lower off the battery"

I would recommend that you do not listen to these "people" in the future when they offer electrical advice. They have absolutely no idea what they are doing.

 

why are you even asking for advice if you think that you know everything nd are just arguing with them?

 

Anthony is not even the OP... not even in the same state.

He jumped in responding to your post and I have no idea why.


Unless he IS the OP and is using multiple TW accounts and fucked up.

 

i have 3 55w lights, i think i meant to say 20a for the fuse...i cant remember

i followed this, but put the switch to the battery instead of the fuse box

 

OK, so you need to get methodical here. The whole system isn't working, so you need to figure out step by step which leg isn't right.

After you reversed "power" and "accessory" on the switch, the lights don't work, -- but at least we're not blowing fuses, right?

That's actually one big step in the right direction.

You're going to need a multi-meter to solve this. Buy beg or borrow one.

The first question is: is there power getting to the switch?

Disconnect the "accesory" line to the solenoid altogether, but leave "power" and "ground" in place. Flip the switch to "on." Does the light on the switch go on?

If not - there's an "upstream" connection problem or (yet another) blown fuse, or the switch itself was smoked when it was wired backwards.

If the light on the switch goes on - connect the "accessory" terminal to the switch - that's the one that runs to terminal "86" on the relay.

Now, with power on, and the switch in the "on" position, Set the multimeter to "DC Volts" on the range 0-50v then put the Red multimeter probe on a contact point at "86" and the Black multimeter probe on a good chassis ground. You should read 12v here.

If not, there's a problem with the switch, or the wire from the switch to the relay. Check for 12 v at the "acc" terminal on the switch itself. If you don't get that - the switch is bad -- might have damaged it when it was wired up backwards. Otherwise - it's a bad wire from "acc" to "86."

Assuming we got 12v at "86" - let's check the relay and it's wiring.

First, - switch "off."

Put the red probe on 30. You should have 12v here- that's pretty much a slam dunk since it's wired direct to the battery. If not - the wire or inline fuse is bad.

Assuming you had 12v at both 86 and at 30 - flip the power switch to "on"

Now put the Red probe on 87 and the Black probe on chassis - you should read 12v here as well. If not, either the relay is bad or it's wired incorrectly. Before you replace it - double check the ground connection at 85. Wit the multimeter set to read "ohms" there should be zero (or near zero - certainly less than one ohm) from 85 to chassis ground.

OK, if you got 12v at 87, then you've pretty much narrowed it down to that connection, or the wires to the lights - since you already tested that the lights worked when wired direct to battery.

Try this out tomorrow - let us know how it goes.

 

dude?....

okay i was just about to say, i never asked a question, i just wanted to help the guy get his lights working, but i hope my own lights are safe

 

And that is perfect, but the wire going to the switch should be fused at no greater than 80% of the switch's rating. If that's a 10a switch, no more than an 8a fuse, but in reality, whether it's a 10a switch or a 100a contactor, a 5a fuse would be more than adequate to protect that leg of the circuit since the relay and indicator light current draw are less than 1a.

That's what I was referring to... If you put a 25a fuse between the battery and the switch, and the switch is a 10a switch, then the switch just became your fuse if you get a partial short between the switch and relay and end up pulling 15-20a... not enough to blow the fuse, but enough to smoke the switch and possibly start a fire.

 

im confussed as hell right now

 

Just a thought....

Quadruple-check pin 87a if you have a 5-pin relay.
That is the NC contact and it is connected to pin-30 when the coil is not energized.
If pin 87a is grounded, it will blow the fuse when the lights are turned off.

 

okay i under stand it now! my switch is rated at 20a and i used a 20 a fuse, im going to put a smaller fuse in tommaro

you acted like i asked the ops question, then questioned the other guy thats really good at wiring, when i did not!