I have a 2011 f150 5.0 w/factory brake controller. My trailer lost it's running lights only. I used a trailer emulator tester and it showed everything but running lights. I checked fuse 67 and 73 under the hood. 67 was popped and I replaced it but still does not work. Could the relay have gone bad? Or other suggestions?

 

Don't think the relay affects running lights. Just the battery charge line?

If the fuse was blown you probably have a short in the wires somewhere. Better find that. Sure the fuse didn't blow again after you replaced it and then hitched up the trailer?

 

No I just used a tester to the back of my truck and I replaced the fuse but no running lights still. I work at a trailer dealership and usually trailers will blow the fuse but rarely does it short the wiring, I called my friend who is a quick lane manager at a Ford dealership service center and he said to try the Relay because they do go bad. Otherwise my Ford Extended Service Plan should cover it. THanks