I just picked up a 1990 Heritage.

The original owner had a cheap set of after market turn signals on the rear. They would only light and flash if you hold the button in.

I replaced them with original equipment rear signals and the same thing happens. I put a new HD flasher in. Can anyone give me some advice. I am going crazy!!

 

make sure that the bubs are able to pull the load from the signal box.also make sure nothing is grounded out (a bolt squeezing the wire etc).

if all else fails then get the wiring diagram, right side tank and check what is not correct.

 

blinkers on 94 sportster just stopped working any help

 

I realize you submitted this thread months ago but I'm working on an '89 softail that is having the exact same problem that you described on your '90. The wiring of these two model years is identical according to the H-D service manual. I think it is a ground problem but have not figured it out yet. In playing with the wiring I could sware I got it to flash once on two separate occations. I was going to try a new flasher today but after reading your thread I think I'd be wasting my time & $$ with that. I am wondering if you ever figured out the problem? I will let you know if I get mine right. Thanks

 

on my 85 you have to hold the blinker button for the lights to blink. that's how they work.