Brake light switches keep burning out

[exbass94]

94 Explorer- The brake light switch is bad AGAIN for literally....*thinking*....I think this is the 5th time it broke. It seems I can get no more than a year or two out of them before they burn out. I went to disconnect the wire from it and the switch was hot! Not too hot to handle, but definitely very warm. I checked the current in the brake light circuit and there is 5.6 amps going through the switch. Is that what it should be? If it is, why don't these pieces of crap last?

 

[shane96ranger]

I forget, does the 3rd brake light go through the little box on the Explorer?

A guy at work had a similar problem on an Aerostar and eventually just ran a new signal from the left tail light up there and used it directly instead of going through the box. His was melting the positive wire rather than the harness. But after running the new wire the problem stopped.

 

[exbass94]

I'm not sure what little box you're talking about. The problem I'm having is with the switch on the brake pedal, not the third brake light.

 

[srteach]

5.6 amps x 12Volts =67.2 Watts. Unless you are running added lighting, that is excessive. Even if you are running extra lighting, that is too much for the circuit. Figure out where you are running higher resistance, and fix it.

 

[exbass94]

5.6 amps x 12Volts =67.2 Watts. Unless you are running added lighting, that is excessive. Even if you are running extra lighting, that is too much for the circuit. Figure out where you are running higher resistance, and fix it.

Higher resistance would result in lower current .

Actually, I just did some calculations and it seems 67 watts is right in the ballpark of where it should be. Apparently a typical 3157 light bulb consumes about 17 watts, and a typical 921 bulb also uses about 17 watts. There are two 921 bulbs in the third brake light, and a 3157 on each side. Adding those numbers up gives 68 watts. Unless someone shows me those wattage numbers are way off, then I'm apparently just getting crappy switches.

 

[shane96ranger]

I'm not sure what little box you're talking about. The problem I'm having is with the switch on the brake pedal, not the third brake light.

Holy hell, how did I get third brake light out of that? Sorry man!!



You actually have less resistance somewhere (short to ground).

My trailer (87 Ranger bed) had a direct short in one of the bulb sockets. Mine blew a fuse instead of a switch though. Do you have the correct size fuse in it? You would think that would pop before the switch.

 

[exbass94]

I think if I had a short to ground the brake lights wouldn't light up at all. They still light up just fine, it's just when I take my foot off the brake pedal they stay on. I can get them to turn off by jiggling the switch. And you know, there's the whole switch getting hot thing...
Like I said, the amperages and wattages seem to be within spec, so I must be getting junk switches (Napa Echlin)