My rear right turn signal went out and I replaced the bulb and still does not work. The front right still works fine but blinks much fast than left signal. Any help would be appreciated.

Replace the circuit board

Replace the circuit board
i'll tell u for sure, u have a bad bulb, i have a 99 tahoe, and that's how i tell if my rear light is out, tha front one blinks very fast, make sure the light u're gettin is a 2-way light too. %100 sure!!!!!!!!!!!

I also have a left turn signal that doesn't work, but only about every other time I start the 98 Tahoe. When it does work, the digital display on the factory radio/CD flashes, as does the light indicating the gear I am in (immediately above the steering column). That circuit board suggestion was one that I feared. Appreciated but feared.

Whats so bad about the circuit board....Merlin means the one in the tail lamp assembly, not one under the dash.

doesnt anyone read these questions? he said he replaced the bulb, but just in case take the bulb out and turn it around and put it back in, i belive you can put them in backwards. at least you can the single piliment ones.
actually its not all that bad if it is the board in the tail light. :iceslolan take a test light and test the board in the tail light, if you have juice to part of the board and not the buld , you may be able to see wear the board is broken, if you can just take and solder it. if you cant be sure where the break is in the board solder a jumper wire from the part that has juice to the part that doesnt. i fixed an entier dash cluster on an 81 trans am this way once. it took some time but saved a lot of money, :2cents: yours sould be a peace of cake. :grinno: good luck
PS
the turn signle flashes faster because there is one less bulb in the circut, sometimes they will not flash and stay on in the dash display.