How to Activate 12-Volt Pin on 7-Way Trailer Connector Using 4-Pole to 7-Way Adapter

Updated 04/22/2021 | Published 04/21/2021

Products Featured in This Question

10 Gauge Wire - Blue Primary - Per Foot

(108)

$1.65

NOCO Genius Smart Battery Charger - AC to DC - 6V/12V - 10 Amp

(164)

$99.95

Ring Terminal - 12-10 Gauge Wire - 3/16" Ring ID

(71)

$1.17

Ring Terminal - 12-10 Gauge Wire - 5/16" Ring ID

(71)

$1.22

40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket

(98)

$9.88

Question:

Can I get a 7 pin connector added to my 2019 Highlander so that it also charges the battery in the trailer as I drive? I have a 3 pin to 7 pin adapter now, but it does not charge my battery.

asked by: Cynthia U

Expert Reply:

If you currently have a 4 pole to 7-way adapter like # 37185, in order to get output on the 12-v pin in the 1:00 position, the black wire on the adapter needs to be ran to the positive battery terminal. You'll need a length of 10 gauge wire which we sell by the foot as part # 10-1-1 long enough to run under the vehicle from the adapter to the battery. You'll want to install a 40 amp breaker like # 9510 inline on that circuit, mounting it as close as possible to the battery. You'll also need 2 of the # 44-5310A ring terminals and one larger terminal, part
# 44-5356A to make those connections.

Due to the distance between the battery and the 7-way and the gauge of the wire, the output from this circuit will maintain a charged battery, but it will not have enough output to charge a depleted battery. You'll need shore power and a battery charger like # 329-GENIUS10 to fully charge the battery.

expert reply by: Mike L