I'm repairing a 05 with A/T and can't get any of the steering wheel controls to work, the light and wiper switches work fine just the audio, cruise, shifter and horn don't. It had blown passenger, driver and driver side curtain bags but all of the wiring in steering wheel under bag look fine. I checked for a fuse for these contols and can't find one. As far as I can tell everything else works fine. I've repaired two 04 with bags blown and had no problems. Any suggestions????

 

Maybe the problem isn't at the fuse box but inside of the steering wheel? I've never opened it up before, but everything has to have a start and end point. I consider the fuse box the end and the stuff inside the steering column the start. Have you checked there? Would a blown air bag effect any of that?

 

Not saying that it wouldn't but I have repaired 2 previously with blown bags and it didn't effect those. They worked fine.

 

FYI It was the slip-ring behind steering wheel.

 

This is totally reaching in the dark here.

But maybe you can diagnose it... this page: http://www.gweep.net/~sfoskett/miata/audiopins/ says that steering wheel controls are connected to pins P and N and apply certain resistances based on the buttons pressed.

So I would disconnect the radio and check the wiring harness wires P and N to see whether you are getting the resistances when the buttons are pressed. If you are getting those, but they still dont' work, then probably the head unit is borked. If you're not getting those, then there's a problem before the head unit. Maybe take out the steering wheel controls and make sure that they are outputting these resistances? If they are, then it's "broken wiring" or something between the wheel and the radio.

Or something like that.

I doubt that the steering wheel controls are "fused', since according to that page they are just switches that short the two pins with various resistance levels.