Fog light help

[Groundginger]

XLT with factory fog lights. Finally got around to hooking up my 20 inch light bar that I’ve had mounted for several months. Soldered in a nice weatherproof plug and heat shrink off of the passenger side fog lamp now have no power to the passenger side fog lamp Which makes no sense to my brain. Little help? Are these wired separately? Being all LED I was thinking the extra draw would be negligible and might have to up the fuse worst-case scenario.

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[Msfitoy]

You probably blew a fuse? A 20" draws considerably more amps than one incandescent fog...

 

[Groundginger]

I will gladly go back and add a relay if someone could tell me where the damn fuse is located.
What perplexes me is that the driver side is still working.

 

[BiilyJones]

Unhook it and see if the fog light works. May be just eating all of the power.

 

[Figarou]

Fog Lamps

The BCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position.

When the BCM receives input from the headlamp switch indicating a request for the front fog lamps, the BCM provides voltage to the front fog lamps.

When the SCCM reads a flash-to-pass or high beam request from the LH steering column multifunction switch, the SCCM sends a message over the HS-CAN2 to the GWM, then the GWM sends the message to the BCM over the HS-CAN1. The BCM disables the fog lamp output while in flash-to-pass or high beams mode

If equipped, when the vehicle is in snow plow mode, the fog lamps are disabled.

The BCM also provides Field Effect Transistor (FET) protection of the rear fog lamp output circuit. When an excessive current draw is detected, the BCM disables the front fog lamp output circuit driver.
Refer to: Body Control Module (BCM) - System Operation and Component Description (419-10 Multifunction Electronic Modules, Description and Operation).



If you draw too much power the BCM will disable the circuit.

 

[Groundginger]

WOW. Thank you for the thorough answer. So hopefully just a matter of installing a relay off the fog lights which should be a low draw and resetting the BCM?

 

[Figarou]

WOW. Thank you for the thorough answer. So hopefully just a matter of installing a relay off the fog lights which should be a low draw and resetting the BCM?

If one side is still working, there's a possible wire problem on the other side.

A relay off the fog light will work. It's how I have mine set up.

 

[Langwilliams]

I installed a separate wiring harness for my 20" light bar. Ran the switch inside. It's powered right off the positive battery terminal.

 

[Stangman570]

Fog Lamps

The BCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position.

When the BCM receives input from the headlamp switch indicating a request for the front fog lamps, the BCM provides voltage to the front fog lamps.

When the SCCM reads a flash-to-pass or high beam request from the LH steering column multifunction switch, the SCCM sends a message over the HS-CAN2 to the GWM, then the GWM sends the message to the BCM over the HS-CAN1. The BCM disables the fog lamp output while in flash-to-pass or high beams mode

If equipped, when the vehicle is in snow plow mode, the fog lamps are disabled.

The BCM also provides Field Effect Transistor (FET) protection of the rear fog lamp output circuit. When an excessive current draw is detected, the BCM disables the front fog lamp output circuit driver.
Refer to: Body Control Module (BCM) - System Operation and Component Description (419-10 Multifunction Electronic Modules, Description and Operation).



If you draw too much power the BCM will disable the circuit.

Yes correct, resistance is directly proportional to the length of wire. Ohms Law 101, so in essence he has placed a big ole in line resistor into the circuit by connecting the light bar in series with the fog lamp. This increase in resistance will slow the flow of current where as I=E/R. So this wouldn't necessarily mean the BCM saw an increase of Current (I) or increased power draw as power can be defined as P=I^2R. So a change in resistance would certainly limit current (I) and overall power.

However, your certainly onto something as the Can-bus is extremely sensitive on these Rangers as discussed in my previous threads. For sure this was detected and shut the lamp down. Just the OP gained a wealth of knowledge and learned you just can't simply tap into the power harness to add lights. Always buy the correct wiring harness to match the lights you want to add. Some smart ass Electronics guru such as myself has already designed a harness with the correct relay, in line fuse that correctly correlates to and speced for the wire harness length, gauge wire, etc.

 

[Stangman570]

Smart ass electronics guru? I believe he connected in parallel, not series.
Regardless ohms Law applies period. You add something to the circuit and you get what you get.

 

[Cabose-1]

Damn computers. Remeber the days we just ran wires all over the place all nilly willy. And everything worked. Or it didn't because of a short blown fuse or burnt wire??

Man electronics where easy then

 

[Stangman570]

ohms law is ohms law, yes. But there is a big difference between series and parallel.

To the OP - I would go the route of adding a relay. Ideally you trigger this with a separate switch. The hassle is better than the potential issues created when you tie into a factory circuit. Fuse, proper gauge, quality connectors, and I also recommend you look for OFC (oxygen-free copper) wire and not the cheaper CCA (copper clad aluminum).

Agreed, but you missed the point. He added resistance none the less. I miss QUOTED on series vs parallel and that's the only thing that you got out of it? Bawaa must have got you with that smart ass Electronics guru. Sorry you took offense bro. But yeah, I am that guru and the qualifications to back it up.

Bawaaa, I know who I am, I'm a dude, playing a dude, disguised as another dude.... This thread is one step away from wrapping wire around an open fuse, to make another fuse, lol. Hell back in the day you could use tin foil and just wrap the glass fuses.

But yeah best advise you gave the OP. Do it right the first time. Solid advice ? ?

 

[Stangman570]

Even gurus make mistakes.
We can’t all be heroes, because somebody has to sit on the curb and applaud when they go by.

Bawaaa only Canucks, it's all ? was just poking fun at ya. Welp when we make mistakes... It just goes up in smoke, lol. We call it smoke theory.

 

[Stangman570]

I’m not Canadian. From the mitten-shaped state. Just a guest up here.

Well I wouldn't hold it against ya, lol. I got a few cousins up in Halifax I give crap all the time. Heck you're close enough just to cross the border then.

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