I had no issues before trailering a newly purchased boat. My trailer brakes began locking up while in reverse so I took my truck to a hitch and trailer place and it was learned that my #10(trailer tow backup lamps relay PCB1/ trailer tow parklamp relay R201) fuse was blown. The fuse was replaced which allowed for the trailer to properly disengage the breaks while backing up. The only issue was that with the new #10 fuse installed the parking Lamps remain on even when truck is off and doors are locked (trailer attached or unattached). I removed the #10 fuse and R201 relay as to not kill my battery. With either items removed the lamps turn off immediately. I troubleshooted the headlight switch and even with it completely unplugged the park lamps remained on.

I replaced the R201 relay with a new factory oem replacement and reinstalled the new #10 fuse. I was excited because even with both installed the parking Lamps remained off even after starting the truck and turning it off. Unfortunately when I pressed the lock button on my keyless entry the parking Lamps came on and would not shut off until I removed the R201 relay.

All my other lights are functioning on truck (with or without trailer) and on my trailer. Keeping the #10 fuse in allows my trailer brakes to function properly.

Surprisingly the owners manual has both the #10 fuse circled as well as the R201 relay.

Edit*** 2006 F150 lariat, factory trailer plug and boat trailer has surge brakes/ no electric controller installed.

 

What is this on? We can't see your vehicle through the Internet! What are you using for a trailer brake controller? Does this still happen if you disconnect the controller?

 

Sorry 2006 Ford F150 lariat. Factory installed 7way trailer plug. I don't have a trailer brake controller installed due to the trailer having only surge brakes.

 

Why does it use a 7 pin when it only has surge brakes?

 

The trailer is 5way and I use a conversion 5 to 7 adapter