Brake Light issue

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So I am having a weird issue. My brake lights are working normally during the day when I'm driving around. But at night when I turn my lights on the brake lights are staying on. However when I turn the truck off and turn the lights on the running lights come on and the brake lights work as normal. I measured the voltage at the lights when the brakes are pressed and getting 12v and 6v when the truck is off and the lights are on. I checked all fuses and the button behind the brake pedal. All seems normal. Also the previous owner replaced the rear lights with LED lights and clear cases (not a fan). I will be trying to replace with OEM bulbs and see if it just the LED that is problem.
 

johnnyreb

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So I am having a weird issue. My brake lights are working normally during the day when I'm driving around. But at night when I turn my lights on the brake lights are staying on. However when I turn the truck off and turn the lights on the running lights come on and the brake lights work as normal. I measured the voltage at the lights when the brakes are pressed and getting 12v and 6v when the truck is off and the lights are on. I checked all fuses and the button behind the brake pedal. All seems normal. Also the previous owner replaced the rear lights with LED lights and clear cases (not a fan). I will be trying to replace with OEM bulbs and see if it just the LED that is problem.
Sounds like the brake light switch behind the pedal--under the dash needs adjusted or going bad. Check and make sure its snug.
 

Motech

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My first thought with your 6 and 12 volt discrepancies is that you have a ground problem. Usually that would affect both tail and brake though.

Do the LED light fixtures incorporate a control module? I have seen some factory rear LED setups that rather than muddy things up with bulky harnesses and additional or multi filament bulbs, they vary the voltage to the sole common bulb power circuit between the single tail, brake and directional bulb.
 
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OK so problem solved it turned out to be the actual LED light. I put new OEM bulbs and everything works as normal. It even fixed the turn signal problem. (the problem was the lights would stay on and not blink.) So got new bulbs and order OEM housing and should be good to go. (previous owner put clear housing's in, not a fan)
 

Tiha

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Good to hear, Kind of wondered if LED had something to do with it, but also see bulbs installed backwards from time to time creating problems as well.
 
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Good to hear, Kind of wondered if LED had something to do with it, but also see bulbs installed backwards from time to time creating problems as well.
I did flip them and it did not help. He didn't put a voltage regulator on or any controller for the LED. Just something to note for future LED installs.
 

goodO1boydws

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LED bulbs when used alone in a circuit (installed in a vehicle that wasn't designed to use them) usually don't draw enough current to allow the original turn signal flasher to do its job properly but if you still have a mix of LED'S AND INCANDESCENT BULBS in the circuit (LED/rears, incandescent/fronts and in the instrument panel for example) they may still work, but would tend to flash more slowly.

(If you have many more LED's replacing the original single incandescent bulbs that have a TOTAL similar electrical draw to that of the original incandescents in the circuit, the flashers would tend to work properly-but it takes a LOT of LEDs to do that.)

There are different flashers that can be used to replace the original one (that was for incandescent bulbs) when replacing incandescent turn signal bulbs with LED's.

The same thing (a difference in speed of flashing) can sometimes happen in vehicles designed for and using only incandescent bulbs, with a trailer towing wiring setup-if the flasher IS NOT CHANGED when the trailer is hooked up. With the trailer's extra electrical load on the flasher (if it is also using incandescents) the turn signals may flash more quickly.
If the trailer wiring was done using a higher capacity flasher, (to compensate for the additional trailer bulbs load) the turn signals would likely flash more slowly when the trailer is NOT hooked up.
(If the trailer does NOT have incandescents but the vehicle still does, the TS would probably still function properly)


Here's a good article on how flashers function, which explains why they can change their flashing rate.

 
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johnnyreb

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Solid advice there. I have been down this road on a diesel pickup.
Another thing that can save you time and money is. Make sure you buy good parts. I have noticed. If the tips on the small bulbs are SILVER--DON,T BUY--CHINA MADE and they don,t work. If the filiment isn,t shaken off--the silver end is loose and they don,t get a good connection. Get the YELLOW TIP ONES--MADE IN AMERICAand they work. Even if you have to get them out of a old junk car--more then likely its a good bulb and alot of times.They will give them to you. Another good area to check out if you have a short. The TILT STEERING WHEEL--ON TOP. Check the little wire. Sometimes it will get between the little spring and cut into the wire coating and drain the battery. Good luck.
 

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