High brake light power draw

[pandaboo911]

My brake lights seem to be drawing an abnormal amount of power.

When I step on the brake, my interior lights dim and the engine dips noticeably. My voltage gauge drops from 14 volts to about 12. That seems to be pretty excessive for 2 bulbs, considering my electric fan draws 20 amps and hardly effects the voltage reading.

The brake lights still work fine. My battery doesn't drain overnight. Just wondering if anyone has experienced a similar issue?

Any tips on a possible short? I don't want to die in a fire.

[turbo55]

That does sound like a short somewhere. If the brake lights still work, maybe the short is after the light. Like if there is a resistor somewhere after the brake light to limit the current flow, I would think the short is between the light and the resistor.

In the meantime, just don't use your brakes!:p

[spdracrm3]

dont forget your also activating the brake booster when you step on pedal so if idle drops it could be a leaking booster ,disconnect and plug the vacuum line to the booster and retry your test to see if idle/voltage still dips....

[Jaxx_]

dont forget your also activating the brake booster when you step on pedal so if idle drops it could be a leaking booster ,disconnect and plug the vacuum line to the booster and retry your test to see if idle/voltage still dips....

the other way to test this is to pull the fuse(s?) associated with the brake lights.

[barry]

Check ground and crossed wires

[pandaboo911]

it's definitely related to the circuit. Same deal with the car off. Drops from 12v to 10.5v.

Bulbs are not blowing and my fuses are good. I'm stumped.

[blk4dr325i]

Maybe the brake light switch?

[Jaxx_]

it's definitely related to the circuit. Same deal with the car off. Drops from 12v to 10.5v.

Bulbs are not blowing and my fuses are good. I'm stumped.

inspect the bulbs and terminals, at least isolate the bulbs out of the equation. I've seen bulbs do very strange things when they "blow" but don't blow... like soldering the filament wire to the base, etc.

If you take the bulbs out (one at a time) and isolate it it's less to troubleshoot. then look at the schematics for that in particular bulb and search for ground shorts along it. It should be simple with a DMM

edit: also keep in mind it might be on another circuit (or circuits) depending on the wiring. A failed bulb that is dual filament could cause shorting issues to a separate fused circuit.