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So just recently my high beams stop working. But my low beams are fine and the flash to pass still works, so I know the bulbs are fine. Does anyone know what this could be? Also all the fueses test good.
On these cars, Mazda decided not to install relays to handle the high amperage draw of the headlights (low and high beams), and instead routed the full 12v through the combination switch. This works great as long as the parts are new and clean - but once the contacts get dirty, the resistance goes up and the lights get dim or stop working entirely. It's pretty common on our cars, and more common in the southern states that get a lot of humidity which adds to the corrosion.
Black Dragon offers a relay replacement wiring harness which plugs into the back of your headlights themselves and uses the combo switch at the column for what it's intended to do - switch the lights on and off - leaving the high amperage draw to proper relays. This is a minor bit of work to install the headlight harness, but will definitely give you much brighter lights, both standard and high beams. Plus, you'll never have to worry about keeping the combo switch clean or you headlights suddenly going out at night on a dark road. It looks like this;
It's cheap insurance and not a difficult project. Good luck,
Thanks much I had tried to clean them with Maf sensor cleaner with no results. So I it was toasted, but that contact cleaner brought it right back to life!! I guess now it time for a relay kit.
I used the pictures as a guide.
Then took 800 grit sandpaper folded over and lightly clamped between a pair of contacts, and sanded down the pitting and peaking. Then cleaned with rubbing acetone. Reassembled the switch, but before installation verified continuity for the different positions.
Yes, your combo switch needs to work correctly in order to switch the relays in the aftermarket kit. In OP's original case, even if he installed the Black Dragon kit, the High Beams still wouldn't work because he wasn't getting continuity across that circuit - which would be needed to switch the relay on the aftermarket kit.
The big benefit going forward is that only LOW amperage goes through the combo switch, which is less likely to arc and get carbon fouled over time, compared to running the full 12v/whatever-amps across it to run the headlights through the combo.
It's a poor design, but common for the era. Probably saved Mazda $millions over the production life of the SA/FB.
