Why is my back-up light coming on when I brake?
- Thread starter ET16
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Try using the brake pedal instead of reverse gear (lol).
Not enough info to tell without a wiring diagram. has the car been hit recently? Normally, back up lights on older cars are fed from a common source, a swtich or relay, and each bulb has ground at or near the socket. A short into the power lead should light them both. What happens when when you go into reverse?
JHZR2
Staff member
If the tail lights are like mine in my cars, they share some ground bussing, and may even have exposed positive conductors that are hard bussing (not wires). If dust/dirt/junk causes an inadvertent connection, this could happen.
Does the brake light come on when you put the car in reverse?
Does the brake light come on when you put the car in reverse?
Originally Posted By: HerrStig
Not enough info to tell without a wiring diagram. has the car been hit recently? Normally, back up lights on older cars are fed from a common source, a swtich or relay, and each bulb has ground at or near the socket. A short into the power lead should light them both. What happens when when you go into reverse?
Strangely, it's just the one side. I'll pull it all apart when I can.
Not enough info to tell without a wiring diagram. has the car been hit recently? Normally, back up lights on older cars are fed from a common source, a swtich or relay, and each bulb has ground at or near the socket. A short into the power lead should light them both. What happens when when you go into reverse?
Strangely, it's just the one side. I'll pull it all apart when I can.
Originally Posted By: ET16
Originally Posted By: HerrStig
Not enough info to tell without a wiring diagram. has the car been hit recently? Normally, back up lights on older cars are fed from a common source, a swtich or relay, and each bulb has ground at or near the socket. A short into the power lead should light them both. What happens when when you go into reverse?
Strangely, it's just the one side. I'll pull it all apart when I can.
Most cars have a "light's out monitor" which tells yhou there is a light out somewhere, some have a system which is specific to the location of the bulb. THose extra circuits can make some strange things happen. There may be a printed circuit board inside your lamp assembly which could cause problems. The "good old days" are no more.
Originally Posted By: HerrStig
Not enough info to tell without a wiring diagram. has the car been hit recently? Normally, back up lights on older cars are fed from a common source, a swtich or relay, and each bulb has ground at or near the socket. A short into the power lead should light them both. What happens when when you go into reverse?
Strangely, it's just the one side. I'll pull it all apart when I can.
Most cars have a "light's out monitor" which tells yhou there is a light out somewhere, some have a system which is specific to the location of the bulb. THose extra circuits can make some strange things happen. There may be a printed circuit board inside your lamp assembly which could cause problems. The "good old days" are no more.
JHZR2
Staff member
Originally Posted By: JHZR2
Does the brake light come on when you put the car in reverse?
Does the brake light come on when you put the car in reverse?
Originally Posted By: redbone3
Many times this is caused by breakage of one of the filaments in a two filament bulb. The broken filament touches the other filament and lights light that shouldn't. Easy fix.
I saw that once with a 7 inch sealed beam. My buddy changed one when the low beam blew and then couldn't turn the high beams off. Internal short in the new lamp powered the highs whenever the lows were on. I can't recall the T Bird rear lighting setup, but I don't know how a dual filament could be used for a brake light and back up light in the same housing. Either filament is going to light both. Turn signal/parking light, yes.
Many times this is caused by breakage of one of the filaments in a two filament bulb. The broken filament touches the other filament and lights light that shouldn't. Easy fix.
I saw that once with a 7 inch sealed beam. My buddy changed one when the low beam blew and then couldn't turn the high beams off. Internal short in the new lamp powered the highs whenever the lows were on. I can't recall the T Bird rear lighting setup, but I don't know how a dual filament could be used for a brake light and back up light in the same housing. Either filament is going to light both. Turn signal/parking light, yes.
Originally Posted By: redbone3
Many times this is caused by breakage of one of the filaments in a two filament bulb. The broken filament touches the other filament and lights light that shouldn't. Easy fix.
Great! I'll take a look.
Many times this is caused by breakage of one of the filaments in a two filament bulb. The broken filament touches the other filament and lights light that shouldn't. Easy fix.
Great! I'll take a look.
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