Yes, you are correct. They are LED's. You won't be able to use your diode dynamics or similar kit to achieve switchback... you're probably gonna have to wait until an aftermarket kit is made specifically for 18+I haven't looked at the back side of one of the 18 turn signal yet , but I would not think you can change the bulbs. From everything I ready they went LED this time. I would be you would have to replace the entire housing. I could be wrong.