Riding a 98 fxd and the turn signals work fine while idling but once I go above 2k rpms the rear goes out and the front goes solid. Checked all the wiring for the turn signals and all looks good to me. Happening on both sides. Any ideas?

 

Your rear bulb needs replace. Vibration is making the broken element come apart. It takes both bulbs with the proper resistance to flash. Harley built that into system to tell you a bulb is out. Be sure to use a Harley rough duty bulb. Auto parts lights will not take that vibration.

 

Woops my bad, forgot to mention 4 brand new bulbs too.

 

The you still have a bad connection somewhere or one bad new bulb.. Need to do the wiggle test on the wires and connections. I have seen on older harles, the little disk that separates the two prongs in the light socket break and let the two wires go together. Creates all kinds of craziness.

 

Hmm.. they are after market lights installed by previous owner so I don't know how old they are. Didn't have the problem when I first got the bike though. Could a grounding issue somewhere else be causing the problem? Or maybe the regulator?

 

Check the connectors at the rear of the bike, it sounds like it is losing contact when the bike vibrates. If that bike has the junction box back there, it is probably the big connector.

 

BOOM, there's your trouble. Wiring done by somebody else. Start at the source and work your way back, wiggling and jiggling the wires with a meter on the termination.

 

That's what I did! Took the back fender off, ripped out the rear wiring, took out old splice points, and put it all back together nice and clean. Turn Signals are acting as running lights too.. Could that be it? They are super bright when not in use and dim down when the turn signals on at idle. They have a set of blue wires in its own harness going to the pos. wires on the turn signals, then a purple wire in a separate harness going to the neg. at the light and the black wire in that same harness is being used as a ground. Both rear lights are set up that way.

 

Well just ordered some dual filament lights for the rear. Looking at the stock turns, that's what they used to be. Hopefully it works!