Did you wire in resistors when you switched the rear to led? Are the side lights also led? Some of the resistors don't have the best longevity and a fast flash will be the result when they fail.
No, I did not and was originally wondering if I would need to. Strange thing is the passenger side blinks normal. The driver's side is fast. The side lights are not LED, just the factory original ones. Just ordered a couple resistors from Amazon, when they get here will give them a try. Thanks for the guidance. Then I will try and figure out the dash light.
Diplostrat, we have the same with the flashers working with the dash light. Strange thing is it used to work with just the passenger side blinker and now it does not work at all (I had a temporary rear taillight setup, 1 incandescent on the passenger side and 1 led on the driver's side). Wonder if somehow the resistors will fix this issue also? Once I get them installed I will pass it on.
On a side note, the ABS light was lit and I was wondering why. This happened when the truck was laid up over last summer when we had the chassis dustless blasted. Finally stumbled on the problem while wiring the taillights. Luckily I popped a fuse while doing the wiring. While replacing that fuse I noticed the ABS ones looked a bit sketchy, replaced them and all is good! Rarely is anything that easy. Maybe the dash light blinker will be the same.