Added an AUX input to my radio the other day and it actually works!
 

Just figured I'd post this up for anyone who finds it useful.

I found a video online for a guy who wired in a very rudimentary AUX input to his corvair radio: https://youtu.be/AhktHMXoSbQ

As it turns out, our truck's AM radio is pretty much the same as this one. So if you follow his vid, and wire the positive lead (with a resistor) to the blue volume switch wire and the ground to the brown switch wire, you'll be able to play all the tunes you like. Be sure you wire in a MONO 3.5mm jack. I think you *might" be able to combine the two positives from a STEREO jack and make it work as well, not sure.

I opted to go the cheap route and just wire in a regular mono jack. I don't know what electrical magic happens when you plug in your MP3 player, as I figure both inputs must be going at this point... If I plug in my MP3 source while I'm on a station, I can still faintly hear the station before I play my music. I've found that if you tune the radio to static, your MP3 input is the most clear- sounding. Of course, you can absolve yourself of any concern and add a fancy switching 3.5mm jack to ensure your AM input circuit is broken once you plug in.

By wiring this cable in and wiring a pair of cheap Advance Auto speakers in series to bring my resistance up, I now have a decent mono setup that still fits under the dash. Don't bother with any songs that use a lot of bass, of course. Naturally, the songs from the age of mono speakers sound the best, but a quick test with a Dragonforce song proved pretty decent :metal:

Re: Added an AUX input to my radio the other day and it actually works!
 

I use a Bluetooth adapter and set the iPhone’s eq to bass canceling and it sounds good with all types of music!