I had to remove the headlight housings to troubleshoot and replace an aftermarket HID headlight ballast on my '07 Tahoe LTZ. Since I had so work so hard to get the housings out enough to get access to the back (problem #1), I decided to upgrade the other bulbs to LED and got the Sylvania lifetime warranty ones to match the incandescent ones. However, when I put the LEDs in, neither the driving, nor front turn signals work, and the tail turn signals flash really fast. Put the old bulbs back in and they all work normal. Any ideas since these LEDs are supposed to be plug and play? Just wasted about 4 hours trying to get this simple upgrade done.