3rd brake light strobe?

Why shouldn't it? It's been around for years including the LED upgrade. A later diagram says it corrects the orientation of D3, but that doesn't make sense to me seeing as Q1 is PNP. Then again, a PNP doesn't make sense - shouldn't it be an NPN? I suspect sentex.ca/~mec1995/circ/motflash to be a better circuit (read the Updates at the bottom). That's referred to from sentex.ca/~mec1995/circ/flashing in turn from sentex.ca/~mec1995/circ/circuits.

Your's looks alot simpler than the one I have. ThanksMy wife thinks bagging a truck means you kick it in the truck nuts

Your welcome. Did you see that kits were available? And the article says that it's better than the 555 version, and has no initial delay. I love the 555, but I learned years ago never to use the dual 556 - it was better using 2 separate 555s. (I did the impossible - an electronic "Halda" - an accurate odometer for Rallying etc; its readout was units of 10 yards/meters. It needed pulse/frequency multiplication. I used one 555 to gate another so one pulse in became about 200 pulses out - similar to the brake flasher. PLLs (Phase Locked Loops) became available later, and now CPUs.) Not that a 556 is used above, but it can typify dual 555 circuits. And the 2nd circuit has only one chip (14-pin quad Schmidt NAND) instead of two 555s. The gates (NANDs) do not have the same problems a 555s - ie, high switching transients, different behavior depending on the manufacturer. And they're about the same price (a bit more than a 555, but cheaper than two 555s). The other thing I like about the 2nd circuit is the revision history - it seems to work. (Note the person that used a battery charger to power it, hence it wouldn't work. That's one for 12volt audiophiles.) The original twin-555 circuit is a bit vague... (D3 direction, PNP vs NPN etc). Good luck!