Turn signals blink quickly with trailer attached
 

Just bought a brand new featherlite 3110, lights worked great then I drove around the block and the signals were blinking as if a bulb was out.

Any ideas? It does this with my boat trailer and snowmobile trailer as well.

The install was done by the dealer too :/

I beleive this is normal. There are some threads on this. Search on hitch, trailer and turn signals

Three potential causes.

First is a bad bulb, but that is unlikely if it happens on three trailers.

Second is a bad ground to the trailer. I fixed a fast blinking trailer bulb with an additional ground connection, as the hitch ball was not sufficient to provide a decent ground. The fast blinking came and went, but an additional jumper wire with an alligator clip fixed it.

Third is a known problem with LED lights. There are a number of posts about this, and there was eventually an update from BMW to address it. Not sure how successful it was, but there are a string of threads about it, and the SIB may be posted here as well when you search.

This an LED lights issue, you need to wire up two 8 ohm resisters, one on each side and the problem will go away. I had the same issue. Amazon.com: CBR 929RR 01 6 Ohm, 50 Watt LED light bulb Load Resistor 2001 CBR 929RR Automotive LED Light Bulb Load…

I had the same problem on my trailer with regular bulbs until I had the dealer reflash the ECU to recognize the trailer. All was fine for 2 years until I decided to try LED light replacements, and they flash fast again. Different current draw.

mgbmwx5- I'll have to give those resistors a try. Did it slow the blinker or brake light response time?

There was a post on here a while back and someone said to use a U Haul 39008 module. I have not tried it but it looks like it will work.

The brake lights are not affected at all. The flasher and lights are back to normal now.

Interesting. My trailer uses the same filament for brake and blinker. I suppose the LED lights I got could be different, haven't looked at them that closely. What I'd really like is amber blinkers on the trailer, and move the lights higher up than where they are at the back of the beavertail. But that's a project for way down the road, first I have to finish building my 911 engine so I can actually have a reason to use the trailer.

Good memory. This was the one I recommended trying in a previous thread (after making sure that it isn't a simple ground problem)

U-Haul moving supplies: LED Light Trailer Module

Update

Turns out it was the LED trailer lights causing the issue.

I bought an adapter harness made by Valley which worked perfectly.

It is part # 39010 and is also available from VW/Audi/Porsche as part number ZVW808004

All it is is a 7RV plug on one end, 3' of cable, and then a 7RV socket on the other end, with voodoo in between lol

Works perfectly.