Chevrolet Repair: 2001 chevy 3500 express van, chevy 3500, proper voltage

Question
Hi my brother in law has a 2001 chevy 3500 express van. When he has the left back turn signal on without hitting the brake pedal it blinks normal. When he presses the brake pedal the same light blinks faster. The light bulb has been replaced so it is not a bulb getting ready to burn out. What could he do to remedy this problem? It has been going on for a few years and the dealer is unable to figure it out. Thanks.


Answer
check your blinker fuse, and then all your grounds and wires to the back light. check all wires for shorts, touching, etc..
dealers dont put fast blinking lights high on there list. it works, your out the door.
sounds  like too much voltage is getting to that light bulb or thro that side.
use a multi meter and check, a good repair manual has proper voltage etc..

hope this helps