brake lights bulb work on running mode but not on braking mode
- Thread starter bapsdds
- Start date
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Whippersnapper02
Senior Member
They are dual filament bulbs so probably the brake light filament is blown.
flyrv9
New member
Yea, I agree with what Whippersnapper02 said - either a bad bulb, or a bad crimp on the wiring at the socket. There were a few threads here about that in the early 5gens. Haven't seen any lately.
The way to troubleshoot is to remove the bulb and either check the bulb with a meter or test light (if you can't tell if there is a broken filament by looking). If you don't have a meter, then just swap in a new bulb (or the working bulb from the other side) and see if it fixes it.
If the bulb is good, then the wiring / crimp is most likely the issue. Turn the lights on and check for 12v at the socket in both places (12v for tail light and 12v when brake pedal is depressed) easier to check brake function with a helper. Be careful not to short the pins with 12v to ground (not much room in the socket). If you determine it's probably a bad crimp, then there are threads you can search on that have pics and descriptions on how to resolve the issue.
The way to troubleshoot is to remove the bulb and either check the bulb with a meter or test light (if you can't tell if there is a broken filament by looking). If you don't have a meter, then just swap in a new bulb (or the working bulb from the other side) and see if it fixes it.
If the bulb is good, then the wiring / crimp is most likely the issue. Turn the lights on and check for 12v at the socket in both places (12v for tail light and 12v when brake pedal is depressed) easier to check brake function with a helper. Be careful not to short the pins with 12v to ground (not much room in the socket). If you determine it's probably a bad crimp, then there are threads you can search on that have pics and descriptions on how to resolve the issue.
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