# Passenger Side Brake Light Won't Turn Off! **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mercury, mariner, batteries, electrical-wiring, brakes, lights\ **Created:** [December 27, 2013, 12:31am UTC](https://community.cartalk.com/t/passenger-side-brake-light-wont-turn-off/82840 "2013-12-27T00:31:58Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![bittyreiss](https://avatars.discourse-cdn.com/v4/letter/b/9de053/32.png) [@bittyreiss](https://community.cartalk.com/u/bittyreiss)\ **Post date:** [December 27, 2013, 12:31am UTC](https://community.cartalk.com/t/passenger-side-brake-light-wont-turn-off/82840/1 "2013-12-27T00:31:58Z")
Last week, I noticed that my PS brake light was on, even when the car was off. I did not think anything of it, and figured I could get it fixed whenever I had some spare time…then my battery died! Even with the batter dead, the light stayed on. I pulled numerous fuses, and none worked to turn it off, so I disconnected my battery (which did the trick). I have not jumped my car yet, but was wondering if anyone had any thoughts? I thought it might be the brake switch, but since it is just ONE light, and not both, am not sure that would be the problem. To note: I have a 2010 Mercury Mariner, 37k miles, and had a UHaul hitch installed about 3 years ago. DR brake light goes on when brakes are pressed. Help! ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [December 27, 2013, 9:52am UTC](https://community.cartalk.com/t/passenger-side-brake-light-wont-turn-off/82840/2 "2013-12-27T09:52:22Z")
You need an auto tech to help you out. The brake lights are typically wired to a single circuit, so there must be a cross-circuit short causing the one light to stay on. Did they install an aftermarket light converter (also known as a logic circuit) to the tail light wire harness to give you a trailer connection? On my 2000 Explorer, it came with a built-in trailer circuit that just needed an Explorer-specific trailer light connector to plug into the factory harness. The logic circuit was built into the truck wiring and controlled by a separate fuse. My 1990 Toyota needed an aftermarket logic circuit to be added. A malfunctioning logic circuit may be back-feeding the PS brake light. Especially if one of the fuses you pulled was for the tail light circuit and the DS light stopped working. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [December 27, 2013, 11:19pm UTC](https://community.cartalk.com/t/passenger-side-brake-light-wont-turn-off/82840/3 "2013-12-27T23:19:38Z")
It could be a right turn signal light that won’t shut off due to a malfunctioning multifunction switch or a short in something else live shorting out to that turn signal wire. ---
**Author:** ![dennisgburt\_159766](https://avatars.discourse-cdn.com/v4/letter/d/e480ec/32.png) [@dennisgburt\_159766](https://community.cartalk.com/u/dennisgburt_159766)\ **Post date:** [November 13, 2019, 5:07pm UTC](https://community.cartalk.com/t/passenger-side-brake-light-wont-turn-off/82840/4 "2019-11-13T17:07:02Z")
bittyreiss - Can you please tell me if the issue was resolved, what is was? I have the identical issue with a 2012 Ford Escape, 39,000 miles, Uhaul trailer harness installed 3 years ago.