Only High Beams Working - Both Headlights
 

My low beams have not been working for the last month. Both stopped working at the same time. High beams work fine (which is what i've been using) and so do the running lights. The truck had stock halogens, but i installed aftermarket projectors and an HID system.

I can't seem to figure out where the issue is and have looked into quite a few forums on the issue. After not finding what I needed, I joined up here! This is where I'm at with the troubleshooting...

-No power to low beam at connector to headlight. I do have power to high beam here.
-I've cut the insulation on low beam wire behind the connector and have no power.
-Power is good on both sides of the low beam fuses. Fuses are good.

Any help would be appreciated

Are we supposed to guess what you're working on?

I indicated when signing up the make and model... Assumed it would be visible to all. Looks like it's not. It's a 2013 F150 Supercrew FX4 with the 3.5L Ecoboost.

Did you check fuses and if you have do you have power to the light socket if the fuses are good.
I have seen both headlights burn out pretty close to the same time.

​​​​​​Fuses are good and no power in the low beam pin connection at socket.

Would recommend checking the relay and wiring associated with the low-beams.
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There is no "relay" in the low-beam system in the stock headlight configuration. However, since he indicated that he has an aftermarket lighting system installed, all bets are off unless it is removed and reconfigured back to stock so we can use the factory documentation.

If this were a factory-stock system, simultaneous failure of both low-beam lights would likely indicate a failure internal to the BCM.

Ummm ya, -but- the OP (cdreger) indicated "aftermarket projectors and an HID system and doesn't have a factory | factory-stock configuration.
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The factory system has to control the aftermarket add-on stuff, that's how they usually work.

Since he's not provided any information about the add-on stuff or if it's been excluded from the testing, we can only guess about it (which isn't a very useful endeavor).

Alright guys, if you need more specific information just ask. First time on these forums so I'm not 100% on the etiquette.

The headlights are a simple HID system (bulbs, ballasts, and capacitors) with no relay harness. Ballasts plug in direct to the factory H13 headlight connectors. Nothing fancy. The housings are aftermarket black projectors which the HID bulbs fit into.

When testing to troubleshoot the issue I disconnected the HID ballasts from the OEM connectors and tested the pin slots on the connectors directly to eliminate any effect from the HID components. In other words I was only resting the stock headlight system.

Could it be the MFS or the Headlight Switch? Hopefully it's not the BCM because replacing those can be pricey!

Can anyone fire me off a wiring diagram or shed some light on the wiring pathway to the headlights so I can start working backwards from the socket connection? If I have power at the fuse but not at the socket, I know the issue is somewhere between the two but I don't know whatcomponents are in between. Thanks!

The FETs (electronic switches) in the BCM as well as the vehicle wiring harness are between the fuses and the bulb sockets. I'll see if I can get a diagram posted either later today or tomorrow, if I have time.

Here you go.

I'd recommend starting by reading the circuit description in the diagnostics, then reading the BCM codes as per pinpoint test A. Your BCM may have faulted if it didn't like your aftermarket lighting stuff.