So you decided to upgrade your car's aging signal light bulbs to LED but as soon as you did that, the flasher would hyper-flash. To solve that you went to Google and quickly found out you could use resistors on each light bulb or you could simply swap the incandescent flasher with an LED flasher. Newer cars do not have LED flashers that can be swapped, so depending on the year of your car you may have limited choices. One other choice worth mentioning is getting true 27W LED bulbs (2.25A draw at 12V).
Let's say you went the LED flasher route. Here are the possible scenarios:
1. LED flasher installed + 4 LED bulbs. Result -> signal lights hyper-flash
2. LED flasher installed + 2 LED bulbs + 2 incandescent bulb. Result -> signal lights work perfectly, but it is not what you want. Look at the solution below.
To have all 4 LED bulbs flash as intended with the LED flasher installed, reverse the power leads on the FRONT bulbs (put + wire to - position, and - wire to + position).