brake lights come on by themselves

[brian.b]

Hey guys my brake lights come on over night sometime and when i go to the car the next day they're hot and my battery almost dead .....is it the switch or what ....is this switch pressure activated...and where could i get one......thanks guys.....

[joefrazer]

The switch is probably bad. NAPA has them, part number SL134.

[brian.b]

Thanks man .......

[Fid]

Yes, buy it at NAPA. You'll pay twice their price on ebay or from a vendor.  It's a problem I've seen a few times. Yes, the battery goes dead fast when this happens.

[Bob L.]

Also, had mine stay on, when I replaced the seal where pedal comes thru floor...new rubber was holding it just a bit down...  killed the battery's charge... 

And had the trunk lights stay on too....  that took longer to figure out.

Bob L.

[dpledger]

A potential quick fix is to blast the pivot where the arm turns with deep creep or equivalent, then work it back and forth  a few dozen times. This often works ad requires virtually no effort or $$.

[joefrazer]

Another reason the lights could be on may be due to pressure being held in the braking system. When you release the brake pedal a relief hole in the master cylinder reduces brake fluid pressure in the lines. If that hole is blocked, pressure is not released and in the worst case (happened to me) the brakes lock.

[brian.b]

is the relief hole in the cap ...cause thinking back my lid was damaged and i jb weld on it cause i couldnt find a lid at the time.....

[retired wrench]

     Jathick a wheel up and see if it turns freely. This will tell you if there is pressure in the system. Just went thru this on an old Dodge truck.

[brian.b]

Thanks for all the info guys I'm going to start on it this weekend ..I'll have a few days off......

[54manhattan13]

It could simply be that the brake pedal return spring is weak an not returning the pedal fully. The brake light switch on my 54 Manhattan is controlled by the travel of the brake pedal.