Turns signal flasher odd behavior
 

This started happening a few months ago. After sitting a while (overnight, or all day at my office parking lot), until the car warms up, the turn signals flash at an incredibly fast rate. After I drive a few miles, the flasher speed goes back to normal.

ill bet you have an intermittent bulb that doesn't flash until you start driving and it jiggles in the socket

signals flash fast if you have a bulb out

I would start by cleaning the connections. Corrosion can cause these electrical connections to fizzle out.

It's definitely not one bulb because the problem occurs with both left and right turn signals. Corrosion is a maybe, Could it be the flasher itself?

I'd check your fuses.
Then I'd check your bulbs and their connections and make sure they're secure.

Then I'd see about your flasher relay.

Definite symptoms of the flasher relay. Seen it several times.

If you haven't gotten the problem located yet. I would start by cleaning the ground connections. There are several scattered around the car. Most strange electrical problems can be traced to bad grounds. If it does it everytime the car sits. Just turn on the signals and while they are flashing fast go around the car and try to wiggle the wires at the ground points. If you wiggle one and the flashing turns normal you have your source.

I assume these ground points are identified in the Bentley book?

That is symptomatic of a flasher dead just on a side : the other one goes very fast.

I have the same issue. I cleaned the socket for the fast bulb, thinking that was the culprit but maybe it's the opposite one thats the problem. If not that, then I'll try the relay. I still have the old high-beam switch and I use it very gingerly, could that be the source?

BTW from my days when I lived in Boston using a turn signal could be construed as a sign of weakness.

They should be in the book. I don't use the bentley manual so I can't say for sure. They are pointed out in the factory service manual. They are fairly easy to locate. Brown wires on studs attached to the body. I just had pretty much the same problem but mine wound up being bad ground connections in the sockets. In my case however the offending bulbs were easy to locate as they were not flashing.

You have actually checked each corner to see if bulbs are not lighting haven't you? Generally to get the fast is because there is not enough current going to the flasher. I know it seems counter intuitive. The flasher is basically a bi-metal heat strip that bends to open and close the circuit. It takes a certain current to work correctly. American cars have what is called a heavy duty flasher that you can install. Those have an independant circuit to run the heat strip and they will work with only one bulb or even many bulbs. Now you can also get electronic flashers that don't use a heat strip.