Turn signal and brake light problems

[Mikko_]

On my '53 Customline the RH turn signals work both front and back, but flashes very rapidly.
On the LH the front lights up but doesn't flash and the rear don't work at all.

RH brake light works and LH doesn't.


All bulbs are ok and I have had the turn signal switch apart and cleaned it with no luck.

Could the flasher relay be faulty and cause these problems?
If so, how do I replace the 2 prong flasher that's in there now with a 3 prong?
(I have access to a 3 prong that I know for sure is working, hence my question)