My truck used 95% of the time to tow a fifth wheel rv. Upon parking the rv, I noticed the brake lights on the trailer and truck stuck on. I tapped the brake pedal several times and they still remained on.
Since the trailer brakes were humming due to the "activation" of the brake pedal, I unplugged the trailer from the truck. The truck brake lights remained on.
I, fortunately did not have this situation during the return trip today. Also, in testing, I noticed that sometimes upon pressing the brake pedal, I can hear a clicking from under the dash. But, not always.
I figure this to be a relay under the dash somewhere. At any rate, I need to be sure it does not happen again. Especially since the brake pedal is what activates the trailer brakes.
Does anyone know exactly what this situation is and what the clicking sound is? Why do I hear it sometimes and other times not? As always, thanks to all for the input. Phillip

 

I've never heard a clicking when mine went bad, but i'll bet it's the brake light switch. If you try pulling up on the pedel it should shut the brake light off.
I had to drive mine like that for a few days till i could get it replaced (remembering to pull the pedal back up after stopping)

There's a few posts on here about that. I'd tried searching, but some for some reaon my internet is slooooooow tonight.... try searching "brake light switch" you'll find what your looking for.

 

Mine did the same thing a few weeks back...messed around with the brake light switch down by the pedal , and they went off.

I keep an eye out now and suppose I`ll be replacing the switch soon....if it`s not on notional backorder!!!

...mine never made a clicking sound though , my little `97 nissan p/up does though kind of sounds like a relay switching off and on when you apply the brakes , then let off of them.