Hello,
I've got a 2017 F-150 XLT 3.5 ecoboost. A couple days ago, I started getting the hyperflash when using my left signal light. I confirmed that it was the rear driver's side signal light that wasn't working. Right signal light works fine -- front and back. Only the right brake light works. Neither of the rear parking lights work (I would not have known that if I wasn't trying to debug the signal light problem!!). I replaced the bulb. The old one looked fine and had continuity on both filaments. The new bulb didn't change anything. I used Forscan for the first time and found some DTCs:
- B1247:15-48 Left rear turn indicator
- B1445:15-48 Rear park lamps output
(both of these will give extension -0A if I run the test with the signal light on and (I think) the headlights on.

There were also four FCIM codes that didn't seem to be related and didn't return after erasing the codes. There were a couple of PSCM codes that DO seem related and haven't reappeared after erasing codes, but I also haven't driven the truck, so they might come back:
- U0553:00-48 Invalid data received from lighting control module-Rear 'A'
- U3003:68-48 Battery voltage

I did a body control module system test using Forscan and came up with 5 DTCs:
- C1D00:11 Park brake apply switch; Additional fault symptom: circuit short to ground
- B1247:15 Left rear turn indicator; Additional fault symptom: circuit short to battery or open
- B143D:11 Headlamp on input; Additional fault symptom: circuit short to ground
- B143C:11 Headlamp off input; Additional fault symptom: circuit short to ground
- B1445:15 Rear park lamps output: Additional fault symptom: circuit short to battery or open

After seeing the headlamp DTCs, I checked daytime running lights, headlights, bright lights, fog lights. Everything appears to function normally.

All of the exterior bulbs on the truck are incandescent and original (except for the one tail light bulb I changed while trying to fix the problem, which was replaced with the same model of bulb). Given this list of DTCs, it seems like my problem is more fundamental than a wiring problem at the back of the truck; however, I'm not sure where to start debugging this. Could it be a bad connector? Bad module? Any guidance is much appreciated!

 

I suspect a corroded connection in the circuitry to the left stop/turn lights.
In general corrosion or poor connections will still allow some voltage (up to the full 12 volts) to be present but this voltage will drop when the load (bulb) is activated causing the bulb to glow faintly. In daylight this glow will be very hard to see. Use a Digital Volt Ohm meter (DVOM) check for voltage at the bulb as the brakes and/or turn signal are activated. Make sure the meters ground side is making a good ground. If you confirm poor connection (voltage present) then I would inspect the connector at the Central Junction Box for corrosion. I do not have wiring diagrams for a 2017 so others will need to chime in with the pin numbers and the connector number to be inspected.
Wiring and splice points may also need inspecction.

 

Thanks Jimboy. I did manage to find some wiring diagrams online, and actually paid for 72 hours of access to the Ford documentation to help with finding stuff. There are two connectors between the BCM and the bulb. One (C405, pin 8) is located behind the spare tire and the other (C316, pin 32) is located under the hood, driver's side, behind the engine air filter box. I started with the rear one, thinking it was more likely to be corroded. It looked fine, and I had continuity from there to the bulb, so I went to the front one. While I was looking for it, I discovered a squirrel nest tucked away down by the fender. The connector, itself, looked fine, but the wire went down into the region where the nest was, and access is terrible. Pretty sure that's my problem because I am getting an open circuit when I test from the connector at the BCM. My next step will be to pull off the splash guard, and I expect that will expose the mess I have to deal with. Hopefully not too much of a nightmare.

 

Sounds like you are making progress. Let us know the final solution.

 

Here are some pictures of what I found. I had to take off the splash guard in order to pull out the rest of the nest, and for much easier access to the damaged wires. The squirrel chewed into the wiring harness in three spots. About 6 wires were damaged in total -- some in more than one place. The orange and grey one is the signal light wire. Spliced them and applied heat shrink, and bundled everything back up with cloth automotive electrical tape. The signal light and tail light works, and there are no error codes in the DTC frame in Forscan. However, I repeated the BCM test and it came up with four codes:
- B1305:01 Hood switch; general electrical failure
- C1D00:11 Park brake apply switch; circuit short to ground
- B143B:11 Autolamp on input; circuit short to ground
- B143C:11 Headlamp off input; circuit short to ground

I haven't noticed any symptoms of problems related to these DTCs, and I'm not even sure if they're related to the squirrel incident. Also, not sure why they didn't show up in the regular DTC list. I searched around under the hood to see if I could find any more damage and didn't see anything. All the lights seem to work normally, so I'm considering this more or less a success, but curious about those codes. FWIW, the hood was open and the park brake was on when I did the test. When I get a chance, I'd like to try this with the hood closed and the park brake off (mechanical park brake).

 

Good catch!

 

Hi, just signed up to this forum as I also have the exact same codes for Parking brake, Autolamp and Headlamp, when I perform the Body control module self test!
Canīt notice any symptoms on my car, but really want to know what these codes are.
@greasyF150 did u manage to figure out what these codes really are?