How to Wire Up the 12 Volt Accessory Circuit of a 7-Way Connector

Updated 04/08/2015 | Published 04/07/2015

Products Featured in This Question

Deka Battery Isolator Installation Kit for Standard Alternators - 8 Gauge Wire

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$34.34

10 Gauge Wire - Blue Primary - Per Foot

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$1.84

40 Amp In-Line Circuit Breaker - Perpendicular Mount Bracket

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$9.84

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

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Question:

2005 Toyota Highlander V6 conventional not hybrid with tow package. I have 4 pin wiring connected to a 7 pin connector for lights, all OK. No need for brake controller at the moment because I have a light trailer with surge brakes. But I would like to wire 12VDC accessory power to the 7 pin connector on the tow vehicle. I think a battery interrupter makes sense to do at the same time. Question - will this kit with a 95A battery isolator be what I need or is there additional fuse/breaker/wiring needed for the 12VDC from the car battery? Related - I only have one trailer needing the 12VDC - is it better/easier to install the isolator in the trailer or in the tow vehicle? Many thanks

asked by: Medwin

Helpful Expert Reply:

The Deka Battery Isolator Installation Kit # DW08769 would be one option for running a power wire to the 12 volt accessory circuit of your 7-way. Keep in mind that this only has 15 feet of wire which may or may not be enough for you.

Typically we recommend people use a length of 10 gauge wire like part # 10-1-1 sold by the foot to power that circuit. The # DW08769 includes 8 gauge wire and a 50 amp breaker. Normally a 40 amp breaker like part # 9510 is recommended.

For an isolation solenoid you would actually want the part # PK5231201. This will allow you to make the 12 volt circuit active only when the key of your vehicle is on.