Passenger Side Blis Constant On

Stangman570

Well-Known Member
Joined
May 31, 2019
Threads
21
Messages
405
Reaction score
1,028
Location
Florida Panhandle
Vehicle(s)
2019 Ford Ranger 4x4 XLT Sport
Apologies for the long post.

Driving around last night I got a Cross traffic and Blind spot system fault. Shortly followed by intermittent air bag fault illumination and the lights on lower control panel for the air turning on and off randomly. I pulled over and turned off the truck and restarted. Problem remained for the duration of my twenty mile trip. Contant faults for the blis and cross traffic and intermittent airbag and lights to the lower panel continued to randomly turn on and off. Also noted that the air controls were also unavailable on the touch screen.They were there but inop. In addition, I noticed that the in cab turn signal indicators rapidly flashed each time I used the left or right blinkers. It was too late for troubleshooting by the time we got back.

This morning I found my passenger side rear tail light assembly with about 1/4 cup of water in it. Removed the entire assembly and removed the blis radar module. Drained all the water out and purged the tail light assembly for about 8 hrs with an old hair dryer with no heat. Ensured all of the moisture had been removed. Found and repaired a small crack on the upper part of the lense.

Removed the rear cover on the radar module and found zero moisture inside, although I did find what appeared to be corrosion on a couple of pins on the module. Cleaned the pins and connector on the module and the wire harness to the tail light assembly. Reinstalled everything, but this didn't clear the fault. No codes were found with my BDX. I've performed the blis reset procedure by turning the ignition off and on twice. This didn't work, I pulled the negative to the battery for about 5 mins while I was checking other things. Doing this hard reset didn't work either. Confirmed that the battery was at full charge, so this part is ruled out.

I thought perhaps the radar module was bad from the exposure, so I swapped it out with the left side that has no faults. I expected the fault to move to the drivers side, but that didn't happen. The fault remained on the passenger side. I tested the original radar module that is now in the drivers side assembly by having my wife drive her truck next to mine. The drivers side blis functions as it should via the drivers side mirror indication. So I know for a fact that that module is good, although it was exposed to moisture.

I went further by completely disconnecting both tail light harnesses on each assembly simultaneously and then turning the key to on. The drivers side mirror LED never came on as expected however, the passenger side mirror LED instantly came on even though both tail light assemblies were disconnected from the truck. Pluging in the drivers side tail light assembly (with original passenger side module installed) and turning the ignition key to on, the drivers side Blis turns on briefly and turns off as it should after testing successfully.

At this point it would appear as though the harness leading to the passenger side assembly might have been compromised. I disconnected and cleaned the connector just to the right of the spare tire on the passenger side. I ohmed out pin for pin this part of the pig tail cable that goes up to the lamp assembly and found no issues. I followed the harness all the way to the mid point connector just in front of the fuel cell on the drivers side and found no issues with breaks or chaffing. Inspected the remainder of the harness to the engine bay and found no issue there either.

I guess it's time for me to pickup a OBD Forscan connector on Amazon so I can get busy checking the SDOR and see if it needs to be reset? On a side note after removing all the water/moisture from the passenger assembly, the random airbag illumination, air control panel issue, and rapid in cab turn signal indicators was resolved.

20220305_144702.jpg


20220305_144657.jpg


20220305_142111.jpg


20220305_142025.jpg


20220305_113312.jpg


20220305_142040.jpg


20220305_142017.jpg
Sponsored

 
Last edited:

P. A. Schilke

Well-Known Member
First Name
Phil
Joined
Apr 3, 2019
Threads
141
Messages
7,012
Reaction score
36,169
Location
GV Arizona
Vehicle(s)
2019 Ranger FX4 Lariat 4x4, 2020 Lincoln Nautilus, 2005 Alfa Motorhome
Occupation
Engineer Retired
Vehicle Showcase
1
Apologies for the long post.

Driving around last night I got a Cross traffic and Blind spot system fault. Shortly followed by intermittent air bag fault illumination and the lights on lower control panel for the air turning on and off randomly. I pulled over and turned off the truck and restarted. Problem remained for the duration of my twenty mile trip. Contant faults for the blis and cross traffic and intermittent airbag and lights to the lower panel continued to randomly turn on and off. Also noted that the air controls were also unavailable on the touch screen.They were there but inop. In addition, I noticed that the in cab turn signal indicators rapidly flashed each time I used the left or right blinkers. It was too late for troubleshooting by the time we got back.

This morning I found my passenger side rear tail light assembly with about 1/4 cup of water in it. Removed the entire assembly and removed the blis radar module. Drained all the water out and purged the tail light assembly for about 8 hrs with an old hair dryer with no heat. Ensured all of the moisture had been removed. Found and repaired a small crack on the upper part of the lense.

Removed the rear cover on the radar module and found zero moisture inside, although I did find what appeared to be corrosion on a couple of pins on the module. Cleaned the pins and connector on the module and the wire harness to the tail light assembly. Reinstalled everything, but this didn't clear the fault. No codes were found with my BDX. I've performed the blis reset procedure by turning the ignition of and on twice. This didn't work, I pulled the negative to the battery for about 5 mins while I was checking other things. Doing this hard reset didn't work either. Confirmed that the battery is at full charge, so this part is ruled out.

I thought perhaps the radar module was bad from the exposure, so I swapped it out with the left side that has no faults. I expected the fault to move to the drivers side, but that didn't happen. The fault remained on the passenger side. I tested the original radar module that is now in the drivers side assembly by having my wife drive her truck next to mine. The drivers side blis functions as it should via the drivers side mirror indication. So I know for a fact that that module is good, although it was exposed to moisture.

I went further by completely disconnecting both tail light harnesses on each assembly simultaneously and then turning the key to on. The drivers side mirror LED never came on as expected however, the passenger side mirror LED instantly came on even though both tail light assemblies were disconnected from the truck. Pluging in the drivers side tail light assembly (with original passenger side module installed) and turning the ignition key to on, the drivers side Blis turns on briefly and turns off as it should after testing successfully.

At this point it would appear as though the harness leading to the passenger side assembly might have been compromised. I disconnected and cleaned the connector just to the right of the spare tire on the passenger side. I ohmed out pin for pin this part of the pig tail cable that goes up to the lamp assembly and found no issues. I followed the harness all the way to the mid point connector just in front of the fuel cell on the drivers side and found no issues with breaks or chaffing. Inspected the remainder of the harness to the engine bay and found no issue there either.

I guess it's time for me to pickup a OBD Forscan connector on Amazon so I can get busy checking the SDOR and see if it needs to be reset? On a side note after removing all the water/moisture from the passenger assembly, the random airbag illumination, air control panel issue, and rapid in cab turn signal indicators was resolved.

20220305_144702.jpg


20220305_144657.jpg


20220305_142111.jpg


20220305_142025.jpg


20220305_113312.jpg


20220305_142040.jpg


20220305_142017.jpg
Hi Stang,

Great diagnostic skills.... Question...how did you repair the crack in the taillight you found cracked? Any idea what caused the crack?

Good luck...Hope you can resolve this.....Is your truck outside the 3 year warranty?

best,
Phil
 
OP
OP
Stangman570

Stangman570

Well-Known Member
Joined
May 31, 2019
Threads
21
Messages
405
Reaction score
1,028
Location
Florida Panhandle
Vehicle(s)
2019 Ford Ranger 4x4 XLT Sport
Hi Stang,

Great diagnostic skills.... Question...how did you repair the crack in the taillight you found cracked? Any idea what caused the crack?

Good luck...Hope you can resolve this.....Is your truck outside the 3 year warranty?

best,
Phil
Thanks Phil! I cheat a little, I'm an Electronics Engineer by trade so I truly love a challenge. I'm still under the power train warranty. I'm at just a tad over 42k on the ole ticker. I usually don't take my vehicles into the dealership unless it's absolutely necessary. I have found a solution for this issue today, so I'll post photos and the solution shortly. It just amazes me that Ford has integrated so much of the system that it has effects on other devices on the Can-bus.

I did repair the crack in the lamp housing with some gorilla glue. I checked the crack by closing off all the vents and main connector point and applied some light air pressure to ensure no air was escaping from the crack. Will have to replace the lamp housing soon, but will check with my local salvage yards first. These buggers are expensive ?
 
OP
OP
Stangman570

Stangman570

Well-Known Member
Joined
May 31, 2019
Threads
21
Messages
405
Reaction score
1,028
Location
Florida Panhandle
Vehicle(s)
2019 Ford Ranger 4x4 XLT Sport
Okay, so we can officially close this thread as solution found and issue resolved.

Had to stop over analyzing the problem and go back to basic troubleshooting 101. Everything kept leading me back to the harness as the fault still existed with both tail lamps unplugged and out of the circuit. When checking the bottom rear connector (pigtail from passenger lamp) at the body harness, I just happened to look over at the rear bumper and found a piece of twig that was wedged behind the passenger side bumper sensor.

I'm thinking no way it's this simple. Removed the twig and turned the key to the start position. Noted that the fault cleared on the dash however, the LED was on in the passenger side mirror. Noted that while the LED was on it was extremely dim, but none the less it was on.

So I went back to the body side harness connector with the key in the run position and moved it around by hand while watching the LED. Sure enough I was able to modulate the LED, and not only that I was able to fault out the Airbag notification on the dash along with duplicating the air control panel and air control inop on the touch screen.

Now I was on to something, with pinning out the pigtail harness to the lamp housing yesterday with a paper clip I guess I just got lucky that the continuity was just right not to reflect an open. This time I took the corrugated tubing off the pigtail and found a couple of wires that looked birdcaged and compromised. Lol perhaps by the twig I found on the rear bumper sensor.

I took and cut the bad spots out and soldered the wires and used heat shrink to shore them up. Reconnected everything and presto all issues resolved no matter how much I flex the line or connector. It truly amazes me with how much integration Ford has done on the Can-bus, that this would have effects on other modules. Now I will have to replace the lamp housing and the pigtail harness to the body harness on the passenger side.

I properly thanked the twig for letting me find it and come across modulating the issue with the harness. Of course the twig wasn't the fix, but it got me to the point of saving about $1500 in diagnostic and repair fees at the stealership. Thank you Mr. Twig!!

20220306_101012.jpg


20220306_104447.jpg


20220306_101340.jpg
 
OP
OP
Stangman570

Stangman570

Well-Known Member
Joined
May 31, 2019
Threads
21
Messages
405
Reaction score
1,028
Location
Florida Panhandle
Vehicle(s)
2019 Ford Ranger 4x4 XLT Sport
One last issue I found driving around after the repair of the harness. The PCM nabbed me with swapping the Radar Transponders from the passenger side to the driver side during my initial troubleshooting. I got lazy and didn't swap them back to their original positions.

Once a few vehicles were detected it shut down the entire Blis and Cross traffic and made them unavailable in the drivers assist menu on the gauge cluster. I immediately knew that this was the issue as my research lead me to specific SDOR and SDOL that must be programmed in the modules should they be replaced. This includes the VIN # that must be set should you ever need to replace modules on the Can-bus. In my case as they were already programmed, I just had to move them back to the original positions.

Verified in and out of traffic on the Interstate with no further issues. So just wanted to pass this additional info along incase someone in the future runs into issues with their blis. Hopefully this will save time and $ to help diagnose their issues.

Bottom line is if you damage your tail lights, you must either transfer your original Radar Tansponders to your new assembly, or you'll have to use FORSCAN to set them up. Even worse you'll have to get the dealership to program them. Hope this helps.
 
Last edited:


ControlNode

Well-Known Member
First Name
John
Joined
Nov 29, 2021
Threads
10
Messages
1,155
Reaction score
2,363
Location
Eastern NC
Vehicle(s)
84 Civic "2000S"/16 Focus RS/21 Ranger XLT
Occupation
Computers
Yeah, when a CAN network gets any garbage inputs it can through the whole system for a loop. Diagnostics can be very time consuming because there is not always a "I should start here" logic when several systems go nuts at once.
 

BGRanger

New Member
First Name
Brendan
Joined
Dec 15, 2019
Threads
0
Messages
3
Reaction score
0
Location
Almonte Ontario
Vehicle(s)
2019 Ranger Lariat FX4
Thanks for the super detailed description, you've saved me literally thousands. In Canada, these taillight assemblies are 1600+ and another 800 for the sensor. That's what the dealer quoted me - and recommended replacing everything.

My lens was also full of water (about a cup). I read your post, took it apart and dried everything out, I thought. Problem persisted. Disconnecting the sensor from the lens, I found moisture and corrosion in the connector (pictures). Cleaned that up, and I'm good to go, everything works.

It looks to me like the sensor connector is not waterproof (it is meant to be dry inside the lens) but the sensor module case is pretty watertight due to that good orange gasket shown in your picture.

Thanks again!

20230616_104645.jpg


20230616_104636.jpg
Sponsored

 
 



Top