turn signal problem

have been having a/c problems, but I added refrigereant/sealant today and so far so good. However, today, my right turn signal went wack. When I turn it on, the indicator on the dash flashes and clicks at a very fast (abnormal) rate, and the right front turn light flashes just as quickly, but the rear right light does NOT flash. Could this be as simple as a bulb? I checked the bulbs in the rear right housing and all filaments seems good.

Thanks

more then likely just bad bulb in front.

yes, it's a bulb. The GM electronic flasher units will flash rapidly to indicate a burnt out bulb. The old thermal flashers wouldn't flash at all when a bulb burnt out.