Can Brake Controller Power Wire Circuit Amperage of 2018 Mercedes Benz GLS be Increased

Published 09/29/2021

Products Featured in This Question

Curt Spectrum Trailer Brake Controller - Dash Mounted Knob - Up to 4 Axles - Proportional

(412)

$259.95

10 Gauge Wire - Blue Primary - Per Foot

(104)

$1.77

Question:

My used 2018 GLS came the factory installed tow hitch packageClass III and a POLLAK round 7 wire receptical. Terminal 4 is +12Volts but only has a 15 amp fuse. Wish to use a CURT 51170 type controller but that requires a 30 amp fuse as do most brake controllers. Does the GLS have the correct wireing near the driver area?

asked by: Tom K

Expert Reply:

To increase the amperage rating of the brake controller power circuit of your 2018 Mercedes GLS for the # C51170 you'll have to bypass the vehicle wiring by running 10 gauge wire like part # 10-1-1 (sold by foot) from the black wire of the controller directly to the vehicle battery. 15 amps really isn't enough for any brake controller to activate trailer brakes.

expert reply by: Jameson C