Troubleshooting Brake Light Failures When Flat Towing A 2019 Buick Envision

Question:

Have a Roadmaster all terrain braking system for our tow carThe red brake lights after working for 2 years do not light up only the turn signal light when brake applied. Brake lights work on our RV ok we have a Monaco Cayman 2011. Our Buick is a 2019 envision. Thank you for your help.

asked by: Drew O

Expert Reply:

The Roadmaster Even Brake Portable Supplemental Braking System # RM-9400 wouldn't affect your brake lights in that manner. You most likely have a short or loose connection in the tow bar wiring which is causing the turn signal to work but not the brake light. You'll need to check all of the wiring running from the tail lights to the 4 or 6 wire port you have on the front of your 2019 Buick Envision for any shorts, kinks, or brakes in the wires or a complete disconnection of any wires. Your wiring was most likely run under your vehicle and could have been damaged by road debris or the connection to the tail light wiring or diode could have came loose. If you need new diodes or extra wire you can use the Roadmaster Universal Hy-Power Diode Wiring Kit # RM-152 to replace any damaged items.

expert reply by: Kevin C