Alternating flashing lights?

heh - funny thing is, there are two bosch relays and a solid state circuit board in these, which makes them much more intricate than any simple two relays and a couple of capacitors.  not to mention, they will flash at a regulated rate, over a very large range of voltage, whereas just using two relays and caps will make the whole thing vary depending on voltage.  aaaaaaanyhow.... two bosch relays, a couple of capacitors, lets say that's all you are into it, and say you knew already just the right value caps to use.  say you put the whole thing in a piece of heat shrink, or - maybe you put it in epoxy like they do.  you're into it maybe $8 (being realistic.... and this is getting the relays cheap - on average, they sell locally for anywhere from $5 to $15 depending on how big of theives the autoparts/electronic supplier is) - maybe as much as $15?  guess what - the entire thing is made by a company called Road Runner, and they're $15 brand new - and unless you add considerablly more solid state into your homemade than 2 relays and some caps, well, need i say more?  $15 for professional setup, or - same amount for homemade that would be questionable to it's comparable quality/durability.

here's a quick pic of an old unit taken from a wrecked car - i would include the wiring diagram for these, but each one comes with a diagram in the box.

Do you have a web link for them?

There's a ton of companies that make these. Try searching e-bay for "wig wag flasher" you should find a bunch. Mike

Wig Wag Flasher John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !