Not sure this helps, but I have one from my 74 that I removed 6+ years ago. It was working just fine, not blowing fuses, etc. Removed it when I upgraded to a Centech.
I know there's wiring differences between a 72 & 74, so not sure it will work for your needs, but if you have no luck finding one, and want it, you can have it for the cost of shipping.