I had a constantly on left dash bulb indicator in dim mode.

Changed expensive flasher and fixed.

My '70 occasionally goes into the "both lights on" mode as described in earlier posts. What has fixed it every time for me was to clean the fuse holder contacts and fuse ends for the turn signals.

Paul

Both times this occurred in my 77 911, one of the indicator bulbs had burst and when replaced, the problem went away - I thought it was an intentional thing that Porsche did to tell the driver one of the indicators needed replacing. Is that right?

I would never buy a new flasher without first disassembling the old one. They typically have cracked solder joints from vibration, just touch it with a soldering iron and they work again.

Bulb wattage issue: http://forums.pelicanparts.com/porsche-911-technical-forum/242578-dim-indicator-bulbs-both-illuminated.html?highlight=bulb

Since I switched to the LED lamps in the back mine has done the dim flash...I have been told to add a resistor to the circut since the LED's don't consume the power and the system thinks a buld is out.