Mimic Blinker Ticking Sound
The flasher that you have WILL be able to work with the new system. Tell us everything you know and we'll tell you how to do it.
Duplicating the waveform and speaker that the LED flasher used will make life easier.
A flasher ticking sound is largely (from memory) an "attack" and a "release" noise - sharp metallic step changes producing acoustic ened=y. You can quite possibly   take an on off signal of the correct rate and on / off ratio. By shaping the attack and decay characterisitics of the edges and feed ing teh signal to an amplifier and then to a small speaker you will get some sort of sound. This may be too simpilstic and yo mau need noise sources and noise shaping and directed playing.


Once you get something that sounds vaguely right you can use a  transistor or few for the amplifier and a pizeo sounder for the speaker etc. End cost could be minimal.

A 74X14 6 x Schmitt gate package would have enough capability to make oscillator, noise sources and piezo driver. Plus lots of playing.