what gives???? when it's super cold out (like 25 or below, especially in the morning) the left turn signal indicator light will not flash. i can hear it clicking and i can see the blinker working on the outside, but the inside light doesn't work. the right side works fine. after driving with the heat on for about 15 mins. it works again. it has never given me any problems when it's not cold outside, just when it super cold.

 

I think you need a higher temp resistant blinker fluid.

 

at least your transmission will shift into gear... I have to sit there and warm it up for 15 minutes, or rev the motor up and it slams into gear... a blinker bulb, while be it an annoying problem, is like crying over spilled milk...

the real question... why do you live where it gets less than 25F??? you're nuts! less than 70F is freezing!

 

My 89 RS does the exact same thing with the blinkers. What gives?

 

only thing I can think of is maybe you need to replace the interior bulb

 

Since eveything seems to be working externally, as a wild guess, I'd say it's may be a bad bulb or connection at the IP. The uber cold makes it (filimant or connection) shrink just enough to keep it from lighting.
The indicator is powered directly from the external lamp wiring.
I don't know the change years but, up to a cetain point the wiring went to the bulkhead. From there a wire jumped back up to the IP for the indicator. The other is wiring runs to the IP harness and then to the exterior lamp via the bulkhead. Maybe with the dash makeover is when that happened.