2022 Lariat

[kemwm38]

In need of wiring info for left side drl on headlight wrap around. Wire was cut going thru firewall during power install. Which under dash module does this wire go to ? Installer disappeared. I have run my own wire from front to under dash but can’t find any info to under dash to jump bad wire. Any info will be greatly appreciated.

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[cfhgarza]

I don't know what module it goes to but here's the diagram for the driver's side plug. Maybe you can trace the colors through the firewall

 

[airline tech]

Goes to BCM, Pin 40 on connector C2280c, keep in mind that the BCM provides internal circuit protection (FET) for the individual exterior lights. You might need to do a BCM reset
C2280c - is the top middle connector on the BCM above the IPC Fuse box by your left knee

With Meter:

Note: To check DRL, place truck in (Neutral) and SET parking brake, DRL will not power in park

Pin 6 to Body Ground (voltage) this will check if you have power to connector
Pin 6 to Pin 4 (voltage) (This will ck ground circuit) wiring (Pin 4 is the ground pin for DRL)

Attachments

• C2280c.pdf
  118.9 KBViews: 34
• Headlights.pdf
  103.2 KBViews: 37

Note Above:
As previously posted in the other thread, before you splice into wire, did you confirm wire was cut?

To check Left DRL circuit, disconnect connector at LH headlight C1021, set up system for DRL to operate.

So, engine running and the following.
Full Daylight, shining on dash, (will not work if low light condition and headlights are commanded on)
Headlight Switch in (Auto)
SET PARKING BRAKE!!!!!
Place Truck in Neutral (DRL's operate in any gear position except park)
At the Headlight Connector (C1021)
With a Multi-Meter check for voltage at Pin 6 and any good Body Ground or Negative Post on Battery - should have 12 Volts. This checks Pin 6 wiring.

Note: Most Meter Test Probes are too big to fit into the connector, I have my own homemade test leads, but you can use (If you are very careful and gentle) installing them into the connector use either a paper clip or a sewing T-Pin, and alligator clip to hold the probe onto the paper clip or T-Pin.

Next check for Voltage between Pin 6 and Pin 4. (Pin 6 = Voltage) & (Pin 4 = Ground) at Connector C1021
Should Have 12 Volts

Now to confirm bad/broken wire in between the BCM and Headlight
Shut Truck Off and Perform the Following

With Headlight Connector still disconnected
Disconnect BCM Connector C2280C (See Attachment) for location.

NOTE: ONLY PERFORM THE FOLLOWING WITH BOTH CONNECTORS DISCONNECTED

Using Multi-Meter (Ohms) Scale
Check for (Ohm Reading) between C1021 Pin 6 and C2280C Pin 40 (Harness Sides)
Should be about 3 Ohms.
This will confirm bad/broken wire in that run, if (0) some meters display (dash lines) then wire is broken or open.
If greater then 3 Ohms, then you have damaged wire with broken strands.

Now for you wire run - C1021 (Headlight Connector) Pin 6 = Grey Wire w Blue Stripe)
The wire color does not change at BCM Connector) C2280C Pin 40 same color Grey Wire w Blue Stripe) Note: This is a 20 Gauge Wire, ensure you run matching wire gauge, the lighting circuit is very picky, and the wrong gauge wire might create issues.
If I recall correctly the C2280C connector view is looking at the face of the connector with it disconnected, some diagrams have it viewed from the back side.
Sometimes there may even be numbers on the connector to help with pin location.
So just check and double check to ensure you are splicing into the correct wire at Pin 40 on the BCM connector C2280C and it is Grey with Blue Stripe, and the same color as the headlight connector C1021

If I am correct as viewing the connector installed on the BCM, the Lower Right wire should be Pin 40 on C2280C (Grey with Blue Stripe) but as I said, check and double check before you cut into it and I would leave a good amount of wire left at the connector say 18 inches or so, for error and resplice capability, basically leave room for error or you will be replacing the whole connector if you don't, sometimes those are a pain to de-pin without damage to the connector.

I would just recommend taking the EXTRA steps in troubleshooting to ensure you do indeed have a bad/broken wire before you splice into the wiring harness, I would hate to see a wire splice repair that does not correct the issue you have, especially on a new truck.
Plus, has a BCM self-test been completed, to reset any internal faults? as if this is still locked in as a fault, it may not work till a reset is performed.
This will be a (B) Body Code, not all Body codes will generate a Dash Light, it can only be found by a scanner or Forscan and it will show up for Left DRL as:
B124B-11 - Short to Ground
B124B-15 - Short to Battery or Open

Hope this info helps - Good Luck

 

[kemwm38]

Appreciate the reply’s. Yes wire is cut. Confirmed at dealership when I took in not knowing this was the issue. Dealership wanted $1800 to fix and were kind enough not to charge me for initial diagnosis. Unfortunately I cannot find installer who did this and I doubt he would take responsibility for it. Should have gone to reputable installer. Lesson learned.

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