Why Does the T-1 Wiring Harness for 2008 Dodge Grand Caravan Have to Draw Power From the Battery

Question:

My question is: If we are connecting the wiring harness, using T connectors, to the 2008 Dodge Caravan rear lights power, why we have to run and connect a cable to the battery? If we are using the back lights power, what is the cable that goes to the battery for? Thanks!

asked by: Wilfred C

Expert Reply:

The actual voltage to power the trailer lighting is drawn from the fused 12-volt feed that is ran to the battery. The connections that attach inline behind the tail lights provide the signal that tells the trailer lights when to activate.

This has the benefit of isolating the voltage that powers the trailer lights from the wiring system that powers the tail lights on your Grand Caravan. A short circuit on the trailer wiring can blow the fuse on the power circuit at the battery or possibly damage the converter, but will not damage the much more expensive to repair vehicle wiring. To keep the trailer wiring isolated from the vehicle wiring, it is important that the 12-volt feed be ran to the battery, not a 12-volt supply on the vehicle.

expert reply by: Mike L