Driver Stop light not working

[bastienlaf]

Hello all, I have been tracking a tail light (LED) issue for a few days now on my 2021 lariat. The problem I have is that the driver side stop light doesnt work. The light itself work but it doesnt change intensity when I apply brakes. I’ve connected the driver tail to the passenger connector and it works fine so the tail light is not the issue. I ran a body control module scan on forscan and i get the 2 following error
B143B:11 autolamp on input circuit short to
Ground
B143c:11 autolamp input circuit short to
Ground
These two codes does not seem to match my problem.
Anyone have an idea where to start with my issue?

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[RangerBill]

Hello all, I have been tracking a tail light (LED) issue for a few days now on my 2021 lariat. The problem I have is that the driver side stop light doesnt work. The light itself work but it doesnt change intensity when I apply brakes. I’ve connected the driver tail to the passenger connector and it works fine so the tail light is not the issue. I ran a body control module scan on forscan and i get the 2 following error
B143B:11 autolamp on input circuit short to
Ground
B143c:11 autolamp input circuit short to
Ground
These two codes does not seem to match my problem.
Anyone have an idea where to start with my issue?

Your codes don't seem to jive with the left stop lamp not working as you stated. Below is a diagram of the autolamp switch. I suspect that your problem might be with connector C422 (pin 29) connection (located in front of left rear tire along the frame rail. I have included diagrams below.

 

[airline tech]

The tie in = The Ground Circuit
G123 = Taillamps, Mirrors, Rear Defrost Grid inc Heated Mirrors, Headlamps & CHMSL
So I suspect you have a power feed touching the ground wire somewhere in the circuit and with your noted inop Drivers Rear Brake light, may be the most likely avenue to inspect.

If you did the BCM-Self Test -and got these codes:
Note: sometimes with these self tests, the test is geared for all switches to be in a normal position, so for instance during the self test, it triggers the Headlamps (on and off), if the switch was in the headlamp position and not (Auto) may trigger the faults you posted as the test was unable to switch the headlights off and back on and registered the (cannot control) as a short to ground fault.
Which both of the codes represent - So its one of those situations where you may be mislead if you do not look at the interweaving circuits (code wise)
So either the switch position generated it or its picking up - Power touching ground and the possibility that the issue is somewhere else on the ground circuit and the only known issue that you have is the inop Drivers Brake light, So start on that circuit and may have to branch out into the other tie in circuits.

C422 - Just under the drivers door, using the diagram above - Check for power with brake applied on Pin 29 (Upstream) to isolate (Upstream or Downstream) of this connector.

And the first connector coming off the taillamp assembly is this one

C4483
Check Power on Pin 2 - I will have to redo my pic above to add the pinout (coming soon)
Note the pic shows RH but the same for the LH (location)

 

[bastienlaf]

Thanks a lot for the very valuable reply! I’ll look that up as soon as i can and update

 

[bastienlaf]

C4483 was the culprit it seems

 

[airline tech]

C4483 was the culprit it seems

Ok, I revised the pic for clarity:

So:
Pin 1 = Ground
Pin 2 = Stop / Brake Light
Pin 3 = Park Lamp

It appears the corrosion on Pin 3 - Park Lamp circuit got hot and it melted the cavity and may be touching Pin 2 and damaged it and they are all possibly touching together.
Corrosion Pin 3 and burn marks Pins 1 & 2.
This would explain the codes you have for Auto-Lamp as it includes the Park Lamp circuit.

How does the Male Half Look?

The manuals only show the Upstream (male) half of the connector, as I stated in the pic.
If I am correct as the manuals do not show it:
The connector in your hand (female) feeds directly up to the Tail-Lamp housing connector, and I think its part of the (Bumper Harness Assembly) or its a direct A to B Run (IDK)
If its a direct run, Then it needs researched for the Part Number or Harness Number.
You may try cleaning and inspecting it, but I suspect some damage needing a repair.

I will dig some more to see if I can find detailed info on that harness, I think I have come across this before

 

[bastienlaf]

Pin 3 broke and is stuck in the female conmector. The other 2 pins (male) are in good shape. I’m thinking about repairing with an additional 3 wire connector to bybass C4483

 

[airline tech]

Here you go:

PN: KB3B-13407-BC - LED Harness with Blind Spot (Shown)
PN: KB3B-13407-AB - Non-LED Harness, will have 3 each connectors for the Tail Lamp End and its a 6 cavity connector at the harness end.

I found the part number buried in my files that I never named

No Harness Number found, which is why its not listed in the manuals.
I believe the reason is that this harness may come included with the Tail Lamp Assembly

 

[airline tech]

Updated Detail:

 

[airline tech]

When trying to locate the above part number, I found that it has been revised:
More available and cheaper

 

[bastienlaf]

Thanks a lot for you help!

 

[Capt Jon]

There was a recall on my 2019 for this problem. The recall said failure of the connector cauld cause loss of the lights on the rear of the truck. It said to inspect the connector for pins not ingaging. It no issue no further action required. My dealer told me they had to change the connector because it was a safety issue. I thought repairing the connector created a possible bigger problem and declined the repair. That was 6.5 years ago and no issues with my truck. So I made the correct decision.

 

[DukeCanBuildit]

There was a recall on my 2019 for this problem. The recall said failure of the connector cauld cause loss of the lights on the rear of the truck. It said to inspect the connector for pins not ingaging. It no issue no further action required. My dealer told me they had to change the connector because it was a safety issue. I thought repairing the connector created a possible bigger problem and declined the repair. That was 6.5 years ago and no issues with my truck. So I made the correct decision.

Hey Jon, was the recall for a particular production time frame? I have a 2019 but don’t recall hearing about this.

 

[RangerBill]

Hey Jon, was the recall for a particular production time frame? I have a 2019 but don’t recall hearing about this.

 

[DukeCanBuildit]

Thanks Bob - my build date was 08/19/2019. Just squeaked by.

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