LED bar tie into fuse box.

[Bobtube]

Hey Guys (gals),

Did some looking around but didn’t find exactly what I was looking for.

I’ve purchased a 120W LED bar. Originally I was thinking I would tie it directly into my fog light switch (fogs were deleted BTW) but I’m confident I’m going to melt everything. So! I’m not exactly happy with putting wiring leads right off my battery, I’d prefer to pull power from my fuse box if possible.

question is: has anyone installed a relay and fuse in the main relay box that’s by my trucks battery? Because that would be reeeeeal convenient. I’m assuming I would need some sort of ford manufacturered relay to put into the box.

thanks for the help y’all!

 

[bobbywalter]

just use the fog switch to run a fused relay.

Amazon.com

150 w isnt too bad.

 

[RobbieD]

If the truck had factory fog lights it should have a factory fog light relay. If the original fog lights were removed but the original fog light relay was left in place, you should be able to run your new lights by finding and connecting to the original wires behind the front fascia which were going to the removed fog lights.

Check if you still have the factory fog light relay; that it clicks when the factory switch is turned on; and that there's still an original fuse on the circuit (120 wats = 10 amps, so you'll need a 15 amp fuse minimum).

 

[Curious Hound]

question is: has anyone installed a relay and fuse in the main relay box that’s by my trucks battery? Because that would be reeeeeal convenient. I’m assuming I would need some sort of ford manufacturered relay to put into the box.

I've tried it on my 93. The extra spaces in my fuse/relay box didn't have wiring connections in them and I had trouble finding the right connectors to fit and lock in. So, in my experience, its easier to install the new fuse and relay separately. Newer trucks may be a different story. But, you can buy the relay and relay base with fuse holder built in very inexpensively and just tie it into a keyed power source that can handle the current (120watts = 10amps). Then run your circuit.

 

[Curious Hound]

Not sure what your knowledge and skill level are. You may find some helpful info here, particularly in lessons 1-4

https://youtube.com/playlist?list=PLyIcCeq49Y5_S6AFE-xNE9u6ibqGgYyf0&si=aayRo7-lT8tUN3kw

 

[bobbywalter]

I've tried it on my 93. The extra spaces in my fuse/relay box didn't have wiring connections in them and I had trouble finding the right connectors to fit and lock in. So, in my experience, its easier to install the new fuse and relay separately. Newer trucks may be a different story. But, you can buy the relay and relay base with fuse holder built in very inexpensively and just tie it into a keyed power source that can handle the current (120watts = 10amps). Then run your circuit.

View attachment 105176

mixed results with those.

 

[Curious Hound]

mixed results with those.

Cool. I haven't used them myself, though I ordered a few a while back and have them in my parts inventory. But they look handy for his application. I normally install separate fuses and relays.

 

[Bobtube]

If the truck had factory fog lights it should have a factory fog light relay. If the original fog lights were removed but the original fog light relay was left in place, you should be able to run your new lights by finding and connecting to the original wires behind the front fascia which were going to the removed fog lights.

Check if you still have the factory fog light relay; that it clicks when the factory switch is turned on; and that there's still an original fuse on the circuit (120 wats = 10 amps, so you'll need a 15 amp fuse minimum).

I was thinking of doing this. I was just concerned about the wiring gauge coming from the relay. I suppose I could just tie new wires into the relay itself but does anyone know off of hand what the rating of this relay is? I’ll definitely put an 15A fuse in place.

 

[Curious Hound]

I was thinking of doing this. I was just concerned about the wiring gauge coming from the relay. I suppose I could just tie new wires into the relay itself but does anyone know off of hand what the rating of this relay is? I’ll definitely put an 15A fuse in place.

Most likely a standard 30amp relay

 

[sgtsandman]

I was thinking of doing this. I was just concerned about the wiring gauge coming from the relay. I suppose I could just tie new wires into the relay itself but does anyone know off of hand what the rating of this relay is? I’ll definitely put an 15A fuse in place.

Per the internet, but more than one source says the same. The general rule for wire gauge for expected amp flow is.

#8 gauge for 40 amps
#10 gauge for 30 amps
#12 gauge for 20 amps
#14 gauge for 15 amps
#16 gauge for 10 amps
#18 gauge for 5 amps - this one I couldn't find with a quick search. So take it with a grain of salt until you can verify.

Beyond a certain length, you have to step up the gauge to account for line loss. I think it's around 15 feet but I'm not sure and it might not apply to this situation.

For the activation side of the relay, it would depend on the power requirements of the relay or the circuit you are tapping into. You would want the wires for your relay activation to be the same gauge so the fuse in the system blows instead of your wire.

 

[RobbieD]

The most recent diagrams I have is 1994 (I only drive the old OBD1 stuff); the factory fog lights were fused at 20 amp in '94. Relays are typically 30A through the normally open (NO) contacts. If your truck still has the factory relay, the associated wiring to a point, and the original rated fuse for the circuit, it should handle a 10 amp load fine. Any wiring that you extend from the factory wiring be sure to match the factory gauge or go larger in size. And make sure that ground the new lights properly.

Reusing the stock setup, if it's still there, to the new lights will make for a cleaner (and easier) installation, in my opinion.

 

[Bobtube]

The most recent diagrams I have is 1994 (I only drive the old OBD1 stuff); the factory fog lights were fused at 20 amp in '94. Relays are typically 30A through the normally open (NO) contacts. If your truck still has the factory relay, the associated wiring to a point, and the original rated fuse for the circuit, it should handle a 10 amp load fine. Any wiring that you extend from the factory wiring be sure to match the factory gauge or go larger in size. And make sure that ground the new lights properly.

Reusing the stock setup, if it's still there, to the new lights will make for a cleaner (and easier) installation, in my opinion.

I am pretty confident (don’t have the truck in front of me at this exact moment, that I’ve got a 10A fuse with some 16AWG wires running off it. That being said if I can pull back both runs of wires from the fogs, I can easily run the power from my relay, to my light bar in parallel. Won’t be pretty but will do the same trick.
Your answer with the 30A relay is exactly what I needed, I just couldn’t find an answer anywhere in that regards. I appreciate your help!