Dielectric grease Holds residual power?

Thread Starter


Joined Mar 24, 2017

I saw this today on my vehicle.
The brake lights stay ON even when Brake is not pressed. What's more bizarre was even after I disconnected the brake switch, the lights stated on.
When I measured the break switch input from the harness it read 6.5volts without brake switch activated. When i disconnected the brake switch, the brake sw input from harness still read 6.5v! No wonder my lights turned on. The light go through a flasher module which can turn on at 5v.

As soon as i cleaned off the dielectric grease in the brake connectors? The voltage dropped to 1v!

I have never heard or seen this behavior Before. Any inputs or suggestions ?


Joined Nov 30, 2010
Find out where that voltage was coming from that it got through the dielectric grease, and assume the grease was not, "dielectric" after it got dirt and moisture in it.

I was thinking the brain has a pull up resistor that need to be grounded to show a brake switch being "on" but your verbiage clarified my answer.