Troubleshooting Flickering Passenger Side Brake Light On A 2017 Ford Explorer

Question:

Hello, I have a 2017 Explorer that I have been flat towing behind a class A motorhome for about 2 years. I the past couple of weeks I have had problems with the rear lighting on the explorer. The pass. brake light flickers when I turn off the engine. The brake light works fine when the pedal is depressed. I have replaced the diodes on both sides. The problem went away for a few days and came back. The motorhome has been in the body shop for the last few months so I don't know if I have the same problem with the rear brake light on the motorhome. I am leaving tomorrow to pick up the motorhome in Phoenix, AZ and should be there by Monday so I should know if it is affecting the motorhome on Monday. I have taken it to an auto shop with no success. Do you have any idea what could be causing this or is there someone in the Phoenix area that you know of that could take a look at it. Thank You Tim Heise

asked by: Tim H

Expert Reply:

Hey Tim, I am happy to try to help you get to the bottom of it. While there are a few things that could cause the brake light to flicker, the most common cause is a short somewhere on the brake light circuit. Since the diodes were replaced and it did not fix the problem, a short would explain the issue. Your best bet would be for you (or your mechanic) to inspect the diode wiring harness, as well as the vehicles tail light circuits and look for any frayed or damaged wire that could be causing a short. Also make sure everything is grounded correctly.

What diodes are you using on your 2017 Ford Explorer? Are they the Roadmaster brand like part # RM-15267? What kind of plug do you have on the front of the Explorer? Did you install it all yourself? I am just curious what you are working with exactly.

It sounds like this is happening even when you are not connected to the RV, So it does make me suspect the issue lies on the vehicle side. It certainly cannot hurt to check the brake lights on the RV just in case. I also suggest testing the 7-way plug on your RV. Make sure every pin is functioning normally and make sure the plug and socket are free of rust or corrosion. A circuit tester like part # PTW2991 will be helpful. Also make sure you have a good ground.

We do have a few dealers/ installers in your area if you are looking to take it somewhere. I have linked our installed locator below. You can just enter your zip code and you can see the list of installers in your area. I would think any RV/Auto shop would do that kind of work. You can also feel free to reach out to me directly if I can be of any further assistance.

expert reply by: Jesse M