LED replacement headlights?

THOMASCB21

MEMBER
2007 CHEVROLET SILVERADO
V8
TURBO
4WD
AUTOMATIC
190,000 MILES

I am trying to replace my headlight/ turn signal Assy's with a set from ADCARLIGHTS. They have a LED controller for the turn signal / marker lights. The instructions say to connect a wire to the turn signal positive, a wire to the side-marker positive, and to the side-marker negative. According to the wiring diagram the side- marker has no negative. Only the turn-signal has a ground. So, confused.

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Saturday, November 4th, 2023 AT 11:35 AM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,089 POSTS

Hi,

The marker lights share a ground with the other lights in the same light assembly. All of the ground wires will be black in color.

I attached a few pics showing how the ground is supplied. Take a look at the schematics and let me know if they help.

Take care,

Joe

See pics below.

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Saturday, November 4th, 2023 AT 10:02 PM

THOMASCB21

MEMBER
2 POSTS

Hi Joe,

Thanks for your reply. I guess I should've said my Silverado is a Classic body style (cat eyes). The wiring diagram I attached shows two different circuits going to the side marker and turn signal lights, turn and park lights circuits. The only one with a ground is the turn signal/park lamp. Is it possible that both circuits use the same ground? I am assuming the BCM is turning off one circuit when the other is energized. So, the marker/park circuit is on all of the time until the turn signal is selected then the marker/side turns off and the turn signal circuit feeds power. Both circuits using the same ground in the park/turn fixture. Sound right?

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Sunday, November 5th, 2023 AT 7:19 AM

JACOBANDNICKOLAS

MECHANIC
110,089 POSTS

Hi,

That is very possible. I checked my schematic and from what I see, there should be two wires at the side marker lamps. What it appears they have done is basically what you suggested.

No matter how power is supplied to the marker lamp, ground is provided at the same place as the signals. So, the ground should be G100 at the lower left of the rad support. As far as the light itself, power can be from two different places, the front park lamp fuse (under hood fuse box) and the two fuses for the front signals in the instrument panel fuse box. Regardless of which power supply is used, the ground remains the same.

So, in theory, where it tells you to take a ground from the side markers, it should be fine to make a new ground or use the one from the signal lamp. It all ends up in the same place.

They make nothing easy anymore. LOL

Let me know if that helps.

Joe

See pics below.

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