Wiring A Brake Light Relay Kit In A 2020 Ford F-150 XLT
Question:
I have a 2020 Ford F-150 XLT and a Blue Ox aftermarket tow light harness. I received a Brake light relay RM-88400 in my Air over Hydraulic kit. How does the RM-88400 connect to that harness? It looks like the Brown wire on the harness connects to the red wire 86. Does this also connect the fuse tap or does the power come from the brown wire in the Blue Ox harness?
asked by: Dan G
Expert Reply:
Hey Dan,
The ground for the Roadmaster Brake-Lite Relay Kit for Towed Vehicles # RM-88400 typically gets tied into the ground for the braking system to intertwine them so that they're active at the same time. When used to prevent turn signals from overriding the brake signal the relay is essentially just a switch that requires the running light signal from the motorhome in order for it to turn on so that it doesn't interfere with the vehicle's signals when not being towed.
We find wiring the relay in Ford's to be easier with less issues if you follow the keyless start installation diagram (attached below) and ensure that your motorhome running lights are on when towing the vehicle. The power will come from the motorhome's running light function in this setup.
Product Page this Question was Asked From
Roadmaster Brake-Lite Relay Kit for Towed Vehicles
- Flat Tow Brake System
- Brake Light Relay
- Roadmaster
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on Flat Tow Brake System
Dan G.
6/18/2024
I installed the relay as you suggested and am still having an issue with the left turn signal not working. We are leaving on a 6,000-mile trip in three weeks and probably need to get the diode to fix the issue. brake lights work and the right turn signal work along with the park lights