Electrical2Go - Online Electrical Supplier
This official sponsor may provide discounts to registered members

Discuss Trailer connection in the Auto Electrician Forum area at ElectriciansForums.net

Reaction score
0
Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

Ready to install a 4 pin to 7 pin trailer adapter on 2011 Subaru Forester. Found this black box with no markings. Note there's no 12 gauge wire coming into the harness as would be needed for trailer brakes. What is this box?
 

Attachments

  • 20210912_090022.jpg
    20210912_090022.jpg
    502.4 KB · Views: 8
CK Tools :) The professionals choice when it comes to Electrical Tools
This official sponsor may provide discounts to registered members

brianmoooore

-
Esteemed
Arms
Reaction score
1,732
You can't just connect trailer lights directly to the car lights these days, as you would have in the past, because the car wires are so thin that they already operate at their limit, and there are lamp monitoring circuits that would get upset with additional lamps.
This box takes a feed from the battery, uses the car light circuits to operate relays, and then feeds the trailer lights with the battery power.
The label mentions stop, tail and turn lights, and the four wires on the out side are enough for this.
 
Reaction score
0
You can't just connect trailer lights directly to the car lights these days, as you would have in the past, because the car wires are so thin that they already operate at their limit, and there are lamp monitoring circuits that would get upset with additional lamps.
This box takes a feed from the battery, uses the car light circuits to operate relays, and then feeds the trailer lights with the battery power.
The label mentions stop, tail and turn lights, and the four wires on the out side are enough for this.
Thank you so much! That makes a lot of sense.
 

Reply to Trailer connection in the Auto Electrician Forum area at ElectriciansForums.net

Top