High beams randomly come on mon my 80 720 HELP KEEP KILLING BATTERY!!!!!!!

[89720]

So my headlights have come on randomly on my truck twice today. Just the high beams. Everything off and then like two hours later they came on. Any help PLEASE!!!!!!!!!!!

[PEZi]

man, i don't even know where to begin... sounds like theres a short somewhere... but where is the question

[seang]

I think I know what is going on here, and I think the problem lies in the headlight switch.

Inside the switch there are 6 flaps: 2 for the high beams, 2 for the low beams, and 1 for each side of the turn signal circuits. These flaps have little lobes that rise up and open the circuit when you switch off. These little faps can get hot and warp, and if they do, it can randomly turn things on when you least expect it. Think about it, if that flap is very close to closing the circuit, then the temperature change from day to night will contract the metal and boom, the lights are on.

I had to "tune" these flaps on my old 86.5 D21 a few times a year. I just carefully adjusted them so they would do what they were supposed to do. If you open up the switch, you will better understand it. It's not that hard to do, there is a plastic cover that pops off and exposes the litte flaps. I would have pics, but I didn't have a digital camera or the internet back in 2004.

[Charlie69]

This is most likely the problem. Ihave seen this on many 720 trucks. it can be annoying and if you can find a new switch for it you can bet that the new switch will do it in time.

[86 720]

It is the headlight switch. As stated before, the "flaps" warp over time and need to be either cleaned or bent ever so slightly.
A quick fix, which I use, is to leave the lights "off" and push the switch to the brights position. I do this on my truck since I have the same problem,

[flinterman2000]

Changed mine to a set from a B12. Wiring is the same here and the plugs are almost identical, its a tight fit but it works and you don't have the problem with the flaps.