The truck is parked in the drive. I noticed when the truck had been parked in the drive I noticed that the tail lights came on and then about 20 seconds later turned off. I checked that the ignition was off, doors were completely closed, etc. It has happened several times. I’m worried the there is an electrical problem that might drain the battery.
You saw this happen only once? Or this happens regularly? Are you sure it was specifically the tail lights or do you just mean lights on the back of the truck - as in maybe the brake lights? Do you have a key fob for this with auto door locks? Where was it at the time?
If these are the brake lights, consider replacing the brake light switch located at the top of the brake pedal. I think those are usually cheap.
Brake lights. They come on for 20-30 seconds and then go off. I’ve noticed it about 7 times. The truck is usually parked somewhere else and I have never noticed this before. It doesn’t get used very often- hence, my concern about this affecting the battery.
Also check the pedal return spring. If it’s weak, the switch may be OK, and the pedal is hanging right where the switch engages.
Easy test is to just reach down and pull up on the pedal. If it comes up to the rest point, then it’s a spring.
If it’s hard to move (should be smooth, not rough or “sticky”), then there could be something to that. May require pedal removal and some cleaning/grease.
Chase
Well, there is reason to worry. I once had a sticky brake light switch that did leave me needing a jump.
So, as noted, check the brake light switch and the pedal mechanism. I’d imagine that right now if you jiggle the pedal a little the lights might go on. You’re probably driving down the road confusing the heck out of people too.
Thanks for all of the comments. I’ve been out of town a lot for the past two weeks (in other vehicle) and have not been able to address. I have an order in for the brake switch, have not picked up yet. I use a solar panel trickle charger for the winter when the truck is rarely used. I plugged that back in hoping to prevent a total drain on the battery until I get this problem figured out. Today - battery is dead. Started fine 2 weeks ago. The battery about 1 year old. I fiddled with the brake pedal as Chase suggested and it seems OK to me. Do you think this could be entirely due to the brake light switch or a bigger problem? Weird that it was fine sitting all winter, a few runs to the city recycle center and now this.
It is very likely the trouble is coming from the brake light switch. You would be wise to invest in a test light probe so you could verify that by using it to see if the switched side of the light switch has power on it. I can’t think of anything else that would allow power to get to the lights except the emergency flashers. The middle brake light would not turn on in that case.
OK, I finally replaced the brake light switch. After many tries for way too many hours to re-install the !@X%! retaining clip, I gave up and took it to a shop. Also had to replace the vent solenoid as the check engine light was coming on and staying on.
So those things fixed - my first time to drive the truck, I get in and the brake pedal goes almost to the floor and the service brakes warning is binging. Good thing I didn’t back more than a few feet - really no stopping power. I’m calling the shop in the morning. Is there something that could have been messed up during the repairs?
BTW, a service guy drove the truck back to my house and I gave him a lift back to the shop. Didn’t indicate any problems - I pulled the truck into a parking spot 10 feet forward and all seemed normal with the brakes.