Do Factory Trailer 7-Ways Have the 12 Volt Accessory Circuit Active All the Time

Published 08/06/2015

Question:

My 2005 Toyota Tacoma has the factory towing package - was a battery isolator included in this to keep a trailer battery from draining the truck battery when the truck is off? If not, should I be able to measure 12+ volts from the battery blade of the 7-wire plug anytime? Right now I get 12+ volts with the key in the ON position but less than 0.1 with the ignition OFF. Thanks!

asked by: Brian

Expert Reply:

For some factory 7-ways they will put an isolator into the 12 volt circuit so that when the key is off the circuit isn't active. It sounds like that is how your trailer is wired.

The part # ETBC7 that you referenced does not come with a battery isolator as for most applications having 12 volts available at the 7-way connector at all times does not pose a problem.

expert reply by: Jameson C