Brake lights staying on.

[Northidahotrailblazer]

Any one see this when adding LED lights? I'm getting 5 volts to the brake lights. Enough to make them stay on slightly. With a regular bulb you cant see it. I unplugged the brake light switch and no change. When I unplug the turn signal switch the lights go off. I swapped the switch with an used one, and now the LEDs are even darker and i'm getting less than like around 2 volts. I ordered a new switch but I don't know where it could get stray voltage from other than a shorted wire right? I unplugged both the flashers and my brake switch and they stay on. I'm going to try a new turn signal switch and try that first.

 

[dvdswan]

Are you still using the stock flashers? I've heard that you need to replace those with ones meant for LED lights. No experience though.

 

[RonD]

Did you say when you unplugged the Multi-function switch the voltage at the brake lights was gone?

If so then that of course is where the issue is, but it could be because of the limited resistance of the LEDs
You may need to install external resistors on those LEDs, not at all uncommon
I think you can also get LEDs with internal resistors now

The LEDs flashers may work, you need two, one for turn and one for 4-ways

1989 used the 2-wire tail light setup
Brake and turn use the same wire and filament in the bulb

So brake light switch sends its 12volts to the multi-function switch, when pedal is pressed
That 12volts passes thru the switch to the two wires(left and right) tail lights
If turn signal is turned on then that one sides brake light 12v is cut off and flasher units 12v is connected

Test each wire on the switch for 12v, key off
Only the 4-way wire should have 12v showing, and the "Flash to Pass" head light wire, these have 24/7 power

 

[Northidahotrailblazer]

Did you say when you unplugged the Multi-function switch the voltage at the brake lights was gone?

If so then that of course is where the issue is, but it could be because of the limited resistance of the LEDs
You may need to install external resistors on those LEDs, not at all uncommon
I think you can also get LEDs with internal resistors now

The LEDs flashers may work, you need two, one for turn and one for 4-ways

Yes when I unplugged the multi-function switch the lights shut off, no voltage to the brake lights. I unplugged both the brake light switch and the both the flashers and I still have voltage back there.

My flashers would not blink at all at first so I ordered an electronic flasher and they flash now, but yeah enough of a draw kills the battery. I had a spare switch but i have no idea if it was any good or not. But it did make the voltage go down. But idk if this was an issue before, i never had working tail lights on this pickup so yea it was a surprise! haha I have two condescend lights maybe ill plug them in and see if they change anything. i really noticed when I left for work for a week and came back and my battery was dead. caused a heck of a draw at 5 volts.

So you think I need external resistors and not the electronic flashers?

This wiring is all 92 ford ranger, it has 4 wires going to each tail light. Running, brake/turn, back up and ground.

When the new switch comes in Ill do some more trouble shooting after that.

 

[Northidahotrailblazer]

Did you say when you unplugged the Multi-function switch the voltage at the brake lights was gone?

If so then that of course is where the issue is, but it could be because of the limited resistance of the LEDs
You may need to install external resistors on those LEDs, not at all uncommon
I think you can also get LEDs with internal resistors now

The LEDs flashers may work, you need two, one for turn and one for 4-ways

1989 used the 2-wire tail light setup
Brake and turn use the same wire and filament in the bulb

So brake light switch sends its 12volts to the multi-function switch, when pedal is pressed
That 12volts passes thru the switch to the two wires(left and right) tail lights
If turn signal is turned on then that one sides brake light 12v is cut off and flasher units 12v is connected

Test each wire on the switch for 12v, key off
Only the 4-way wire should have 12v showing, and the "Flash to Pass" head light wire, these have 24/7 power

So I got my new multi-function switch in and its I still have the same issue. Dug into it some more, tested wiring from tail light plug to the plug on the fender no issues found. Good Ohms. I pulled the Multi-function switch down and its letting voltage by almost 6 volts. so with the part of LEDs having limited resistance I plugged in to regular condescend oval lights and everything is working as it should. The multi-function switch shuts power off like it should. Voltage went to zero and my battery draw is gone. So I'm guessing I need to wire inline resistors in. Do you think these would work? I made the tail light wiring a little short so this will kill two birds with one stone. But not sure how many i need or if these will even work? Internet says a 3157 bulb has about a 2 amp draw so I'm guessing these should work.