So a few months ago I was starting my car for the first time after a winter of storage and I had let the old battery untended since it was due to be replaced. It was pretty flat so I boosted it with a deep cycle marine battery that I have, not realizing in the dimly lit garage that I had reversed the polarity of the boosting battery. To my defense, Mazda in their infinite wisdom places a black rubber hood over the POSITIVE terminal, not the universal color of RED!!!

So because the car battery was so flat, there were no fireworks and I attempted to start the car. Nothing. Then I notice and smell small puffs of smoke.

So what got damaged? Luckily the Fb is so primitive that nothing really critical was damaged. The main fusible link blew so I replaced all three with modern Bussmann style fusible links instead of the original wire loop ones. My stereo amp would have also been irreparably damaged but luckily it was protected by a built in fuse which did its job and blew.

The only other fuse to blow was the one that controls the hazard lights and interior dome. When this was replaced, a terrible continuous and loud shrieking buzzing alarm entailed. I finally traced it to the flasher box which is located to the left of the steering column, under the dash. Unplugging the large multipin connector silenced the noise - but also disabled a lot of light and alarm functions. Removing it was also extremely difficult because you really can't see what you're doing nor can you contort yourself to get in there. Seat and steering wheel removal is a must. While two 10 mm hex nuts are just accesible, the third one is simply impossible to reach without tearing the dash apart. Luckily, the flasher box rubber mounting grommets can be removed via a slot so you don't need to remove the third hex nut, you can wiggle and slide the flasher box out.

I put out a want ad on the forum ... only one person responded and the price was very high. I resorted to eBay and found one from a 1981-83 Fb for $25. When I got it, I realized it was not the same as the one from my '85. It is stamped "B" instead of "D" and there is a one blade connector vs the two blade connector in mine. I hooked it up to the main multipin connector and left the one blade connection free .. and everything worked. Except the key in buzzer sounded wrong, very tinny and vintage sounding. The correct one was also available on eBay for the same price, just mislabelled as Rx7 relay set instead of Rx7 flasher box.

Now everything is correct and condition A-1!

 

Good to here you figured it all out and also interesting to know what gets damaged.

I would "hazard" to guess the flasher should have had a fuse from the factory.