I live, part time, in Arizona and when my cars interior heats up the turn signals blink very fast. When the car is cool, normal blinking. I have had the turn signal stem (at the steering column) replaced twice. It helped for a short time.
year, make, model?
Replace the flasher - about $2 for most cars, unless you’re rolling around in a Bimmer or Land Rover.
I agree, replace the flasher unit. A few dollars in most cases.
Also check the bulbs and make sure they are all working. A failed bulb will make the turn signals flash double-time.
In many cases, it’s the lamps, even though they appear to be OK.
Yes, check your lamps first.
I’ll third that…Speedy flasher usually means ONE or more of the bulbs is out.
Along with the others, I suggest checking to see if one or more bulbs is not blinking WHEN THE FAST BLINKING IS HAPPENING. In other words, checking when the flash rate is normal won’t help, but if one bulb is not working when you get the fast blinking, then it may be the socket or the bulb is bad under high heat conditions.