It is under the passenger dash. Metal case about 4X3X2 with a 3 pin cannon plug on it. I have seen them on Ebay, I am going to retrofit a 3 wire solid state truck flasher that is a little more available, Made by pedersen if I recall.
Was going to take a run at fixing mine, but they potted it with a really tough material(won’t dissolve, wont melt) so I might just machine it out and re-use the case/connector with the commercial flasher module...