Trailer lighting problem

I need some advice from the electrical wizards… I rewired my trailer 3 weeks ago with LED lights. It’s a straight set-up, as the plug-in wires go straight back to the trailer’s brake lights. The lights worked fine the first couple of trips. However, now when I turn on the headlights a fuse blows on the van and I lose the van’s back lights and the trailer lights. The brake lights and turn signals work though. Your advice is greatly appreciated on this because I find myself driving to and from P4 in the dark quite often. Thanks. MIKE