Brake lights come on when headlights are on

when I turn my head lights on, my right and left brake lights stay on. But the Center tailgate brake light does not come on however until I depress my brake pedal. As long as my headlights are on, my rear right and left brake lights will stay on.

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I’m thinking that your L/R brake lights don’t work at all and it’s the tail lights that are on. You would mostly be told to check the bulbs by almost anybody commenting here. After that, there may be no further testing required if the bulbs are out.

thank you for the reply, but it is definitely my brake lights that are staying on, as I was going down the road, behind my vehicle was lit up like down town new york. it really jumped out at me.

Now we’re into short circuits or body control modules. There may be good reason to bring it in and let the shop guess at it. You may need some luck.


Yes, expect to pay some $$$ for the diagnosis. Might be something simple, but electrical gremlins can be hard to track down.


an improperly installed bulb or a poor ground have been the most common causes of that problem for me @dmercer1962_178366

Ground problem is possible.
Also possible the dual filament bulbs are wired incorrectly.
Do the brake lights come on brightly when the headlights are off?

i just had someone follow me and this is the resulting observations:

  1. When my light switch is set to auto(meaning headlights won’t come on till dark) (and it is currently daylight), everything worked normally. Brake lights stayed off until i depressed the brake pedal, at which point they would come on and work normally.
  2. If I ever changed my switch position to anything that would engage headlights, my right and left rear tail lights would change from tail lights to brake lights constantly, regardless if the brake pedal was pressed or not. The center light on the back hatch would only come on when the brake pedal was pushed.

what year is your explorer?
you might have a bad Multi-purpose directional switch being your auto headlight function is on it too.

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it’s a 2014

I would say that should be the one of the first things to check.

I think there may be a defective dual filament bulb where one filament is touching the other filament. This could either be in the parking lights or in the rear tail light bulbs. Try turning on just the parking lights. If the brake lights come on, this would suggest a bulb might be at fault, since on most cars, the parking lights come on with the headlights. Try removing one bulb at a time. If you remove the left parking light bulb and the brake lights stay lit, replace the bulb and thén remove the right parking light bulb. If this doesn’t solve your problem, replace the bulb and try the same procedure with the tail lights. It doesn’t happen often, but a cross connection may occur in a double filament bulb.

Well I think it is shop time but yeah I would be fiddling and replacing bulbs just in case. Also might want to clip a jumper on the bulb socket for a secondary ground. The other thing I would ask is if there has been any exhaust issues that might be heating wires up or wires that have fallen down on the exhaust and melted. Get under and take a look.

On my Buick wagon the wire was touching the exhaust in back. I’d put a fuse in and as soon as the car warmed up it would blow the fuse. Separated the wires and it was fine.

When I was a kid I had hit a rock or something with out 61 Merc and punched a hole in the resonator. It developed 4 way flashers when either turn signal was on. Shop had it and disassembled the steering wheel etc. and gave up. I crawled under and found the melted and fused wires in back.

Just some stuff to try or look at a schematic if you’ve got one to try and narrow it down, but count on it going to a shop.

Another idea does it have a trailer towing set up if so could be something in the wire harness going to the plug for the trailer light’s.