Left turn blinker normal . Right turn blinker blinks about twice as fast as the left. Bulbs are good.

What the heck is causing this?

 

You checked bulbs front and back? Usually this is a symptom of a burned out bulb. You're not running LED's are you?

 

I replaced the front today and both right rears are blinking.

Are these controlled by the small blinker can that 's about the same size as an old 35mm film can?

 

if it draws too much voltage,hook up a trailer the second set of lights will cause to blink fast,bad ground or poor ground... all a blinker basically is a bimetal strip of metal trip the blinker and the bimetal strip makes contact light comes on couple secs later bimetal heats up one side expands the other contracts breaks circuit light goes out so any resistance in the curcuit will cause this..all likelyhood the problem is the light socket

 

The bulb I replaced (which had only been in for about 6 weeks) did show some evidence of corrosion. How can it be cleaned out?

 

Good try but the flasher in a C5 does not have a bi-metal strip. It is an electronic circuit.

Peter

 

Try cycling the hazard switch a bunch of times and see what happens. Sometimes, they will start to work again if you do that. If so, then the flasher is failing and you'll have to either replace it or bypass it. The flasher circuit is built into the hazard switch.

Also, make sure you didn't put the front bulb in backwards, I don't think it would fit right but maybe it could be stuck in enough to work.

The C5 flasher is electronic and it will flash fast if it loses some of the load. Other GM vehicles have the same type of thing. This is to indicate a bulb has failed.

Peter

 

Make sure that one of them isn't loose. This happened with mine when I changed over to the european style taillights. I didn't realize that you really have to push them in hard. The lights worked but blinked fast indicating that one was burnt out which it wasn't.

 

thanx lionelhutz was unaware of the inner workings of modern flashers; it appears to do and react in the same way ,that is that it is load sensative too much or not enough resistance in the circuit causes it to blink fast.Advice to cycle hazard few times if it works after that,just what does that tell,bad flasher? Not being a wiseazz seems to be a pretty simple circuit mfgs. have made more complicated,butmy advice do simple easy and no cost procedures first.corrosion in socket go to any plumbing supply store they sell small round wire brushs fit light socket perfect brush it out real good.If you have an OHM meter ***** offending light socket ground wire w/pinconnect ohm meter to it the other end of meter to brass body of bulb installed in bulb socket any resistance there socket is dirty/bad If corrosion is present after repair di electric grease in socket and base of bulb after repair to prevent repeat performance...PS I've only seen this once in my 40 plus years as a mechanic replaced stop/turn signal bulb and blinked fast on rite turn onlyafter much checking it seemed that when bulb was made a strand of copper wire was trapped and soldered in place BETWEEN STOP/TURN AND RUN LIGHT ON THE BOTTOM OF THE BRAND NEW BULB when rite turn energized turn flashed fast, in daylite you didn't notice all run lites flashed also

 

Really?? Backwards will make a difference?