There was another thread out there about this a long time ago and I don't want to resurrect it. I've been towing boat trailers with incandescent lights without ANY issues with 4-pin and 7-pin. I borrowed my buddies 7-pin toy hauler trailer for the weekend and ALL the lights work, except the running lights. Luckily I'm towing during the day. So I read that I should just add an ohm resistor, specifically a 10ohm 25W resistor, on the turn signals of the trailer. The resistor will have to be installed in parallel with the turn signal(s) to the ground. Since this isn't my trailer, has anyone simply added the resistor to the truck permanently at the connector? Are there any issues with doing this?