turn signal blinker too fast

You need to get some extra resistance in the line to compensate. Measure the resistance of the bulb in the current setup, then measure the resistance of the old two bulb setup. I don't know if they are wired in parallel or in series, but if you just measure from the signal wire to ground you should get a good reading. Subtract the new reading from the original reading, then go get a couple of 1 Watt resistors from Radio Shack and insert them between the signal wire and the bulb.

 

might find flasher unit with different specs....

 

Could I ask you to do an experiment? (I believe that not all flashers are the same gizmo inside, and my initial guess would have been that you need to have less resistance, i.e., more current draw, since the two bulbs in the stock 512TR set-up are wired in parallel and the direction bulbs themselves are 12V/21W for both the 512TR and F512M -- but I don't know the 512TR flasher.)

If you plug in the original two bulb system on one side (which you say flashes correctly when activated), what happens when you remove just one of the bulbs -- does the remaining bulb flash faster when activated?

PS -- you can't use a multimeter (which is very low current) to determine the resistance of the bulb filament -- when "on" (i.e., very hot) the resistance of the bulb filament will be higher.

 

One way to change the flash rate is find a bulb with the same base but different wattage. I.e. if your present light is 10W, look for a 15W version.

Adding resistors is hokey...but some like hokey, just not my thing. If you insist on hokey (I'm starting to like that word), the easy way, to determine the resistance is to measure the current and voltage with the light on. Using the basic formula Volts=Amps x Ohms, divide the voltage by the current to determine resistance. Further formula is Watts = Volts x Amps

 

Either get the flasher from the 512M that is designed to flash at the right rate with the bulb setup, or do what Paul suggests and see if you can find a bulb that matches the flasher better.

These things have a bi-metallic strip that heats up as current flows through them, causing the metal to bend and break the contact. So typically, when a bulb is out, less current flows, and the flash time increases....meaning the flasher goes too slow.

If the flasher is going too fast, it has more load on it than it is designed for, which implies that the two bulbs in the TR were in series....a little strange. In this case, the resistor trick would fix the flash rate, but it would dim the bulb. Take a look at the schematic for the TR and see how the bulbs are wired.

Birdman

 

On a TR, the two rear direction signal bulbs on each side are in parallel. I'm not going to look into this because it's not my homework , but the 2nd bulb not only drops the resistance it might up the total inductance so that the current inrush rate is slower - which slows down the heat build-up - which slows down the flashing (even though the steady-state current is actually higher with two bulbs). I just did confirm that if I unplug one of the two direction bulbs on my TR at the rear, the remaining bulb flashes about twice as quick.

I'm not even sure that adding a resistor in parallel would work (although it might be worth a try, but it would need to be a d*mn big resistor -- like 7~10 Ohms/20W to simulate a bulb, and it would be running fairly warm) -- the only other option (using the same flasher and single bulb) is to add the 2nd bulb in parallel and then hide it inside the trunk where it can't be seen (or melt anything)

 

I resently changed a flasher unit on my 348.
there are different specs on units that have the same pin out
for the connectors.
some of the flasher units have different watt specifications for
"different bulb usage" like 3 bulbs or 2 bulbs.
they are pretty common and are in auto stores.... there isn't anything
special about a ferrari flasher unit. other than the fact that it's made
in europe. hacking the circuit with bulbs and wires would be the last
attempt that I would use.