My new to me 4runner appears to have two personalities, with the lights off the brake lights work just fine. With the lights on it appears that the running light and brake light filament are both illuminated at the same time.. Mind you it's only on the drivers side as well... Any suggestions out there would be much appreciated..

thanks,

rick

 

so i did a little research on it and the running lights and the stoplights are pretty simple as far as wiring goes. the running lights hot wire runs thru the headlamp switch. which interrupts the circut. The stoplight hot wire runs thru the stoplight switch (on the brake pedal) and they share the same ground wire.
So basically they have completely separate systems to run each filament in the bulb. the only thing i can think of is maybe you have a short in one of your hot wires. i would look at the wires coming out of the back of the taillight housing they are exposed a little there. or it could be as simple as a bad bulb.

does your truck have trailer lights? someone else's funky wiring job could have something to do with it.

 

No trailer lights, I'll check the wires. I replaced the bulb but that was when there was no brake light, this new one could possibly be FUBAR, thanks for the research

Rick

 

just to clarify when u say there was no brake light do u mean there was no bulb / bulb wasn't working. or there was no taillight housing.

 

Everything was installed just that when I turned the lights on both brake and running light filament were illuminated at the same time, that was a new bulb too.. Last night I replaced the bulb and it seems to be working now, could have been a faulty bulb, I'll drive for a bit and see if it holds up. Otherwise it's possible there's a short if it happens again..

 

good to know. never heard of a bulb doing that must be some quality chinese engineering. lol

 

Check the bulbs, might be someone installed single filament bulbs (1156) instead of dual filament (1157) or they could be bad bulbs (internally shorted).

Bad ground connection at the rear lamp is also likely. As noted, dual filament bulb, common ground. If ground is missing, then you have both filaments in series and you get both filaments lighting at the same time. Have had this problem on my VW a couple of times.