jstcruzin

Turn on power and new aftermarket lights come on time. Turn the key and start it and they go out. Why is this happening? Any help would be great.

Stang69428

Do you have your brights on? I don't think they will work if you do unless you have enabled Bambi mode with Forscan.

jstcruzin

nope. Highs are almost always off, just markers or head lights no fogs

Bluegrass

Those lights will turn on with the Yellow Markers or Low Beams as long as the >separate< dash switch is operated On, for them..
They are turned off when high Beam lights are switched On, by Law unless changed in Program..
A lower Right Dash area Green light will light up when they are On.
If some Lamp change has been made or some other change, there may be a compatibility issue of some sort.
Have you given all the info?
Good luck.

jstcruzin

I appreciate the info but I do know how the light system is supposed to work. I guess not all lights work on the system. I did say but maybe I wasn’t clear on it. My fault…I put new/different aftermarket fog lights on the truck. What I don’t understand is why they would work with the engine off but don’t when the engine is on.

artsr2002

What lights did you install? Are they just fogs or do they have additional lighting capability built-in like DRL or turn signal?

jstcruzin

fogs and turn signal. I didn’t wire up the turn yet

jstcruzin

These are the lights. Came with the new bumper I installed.
Here is something to add I just noticed. If the auto start/stop turn the engine off the dogs come on. As soon as I release the brake the dogs go back out but light for the dogs remains on in the cluster. 🤷‍♂️

Bluegrass

Now we are getting somewhere.
2018, is the truck originally Halogen lighting or LED?
Are you mixing Halogen with LED? The Body Control Module is different performing between the two, for voltage.
If yes, a non running vehicle supply voltage is in the low 12 volt range. The battery state of charge level.
A running vehicle is in the mid 14 volt range.
Your new lights may not work at that level without some other considerations.
We need to know about the Lights to help solve the issue or the mfger needs to be consulted in some way.
Good luck.

jstcruzin

I had the original halogen bulbs from the factory. I changed them for a sealed led unit about a year after I bought the truck with no issues for years. Because I had those leds, it surprised me these are an issue while running and not while at a standstill (no engine power). Figured an issue of all or nothing may occur with cheaper lights but not sometimes on/off. Now what you’re saying makes sense. Would adding some sort of resistor to power side be needed to get the volts back around 12v than the 14v while running? Would that work? I’ll also try to reach out to the seller and see what they say.