Does anyone read the TOS?

http://forum.allaboutcircuits.com/showthread.php?t=53904

How did this thread get to be two pages without being locked?

It is from 2008

Back when people were wild and reckless and electronics was conducted like gunfights in the OK corral.

Yup, this thread was around before the TOS was updated to prohibit automotive discussions.

 

I know this is an old tread, but the question is timeless, so I'm replying for the benefit of future readers.

I've always solved these things using SPDT (Single Pole Double Throw) relays in the past, but because non-American cars tend to disconnect a wire when off instead of connecting it to ground (so you get either 12V or floating, while you need 12V or ground), you end up with quite a few relays.
You do this by connecting the coil of the relays to ground and the other side to each of the signals (right turn signal, left turn signal and parking light), the Normally Closed pin to ground and the Normally Open pin to 12V. The common pin if the new output.

You can now connect the new output from one of the turn signal relays to one side of the coil of a relay and the new parking light output to the other side. The relay will then switch on if either parking light or turn signal is on, but off if none or both are on.

Hence, in this case you end up with 5 relays (7 if you also want to combine brake light and rear turn signals in one bulb as well).

I recently learned another trick. If you first use 3 SPDT relays to convert the floating/12V signal to ground/12V, you can use a simple rectifier or diode bridge in place or a relay or an XOR gate to produce the wanted effect with the marker lights.
Connect the (ground/12V) parking light wire to one of the AC inputs of the rectifier and the (ground/12V) turn signal wire to the other, then connect the plus and minus output from the rectifier to the marker light. This will work both with LED lights and normal bulbs (provided you use a strong enough rectifier).

A picture is worth a thousand words. Draw a schematic.

 

Yup, this thread was around before the TOS was updated to prohibit automotive discussions.

Drum roll....DerStrom8 hits 1000 posts!

 

Drum roll....DerStrom8 hits 1000 posts!

Wow, I didn't even notice! Thanks MrChips

 

It is from 2008

Back when people were wild and reckless and electronics was conducted like gunfights in the OK corral.

I need to learn to look at dates and realize that for some reason members like lupisak have nothing better to do than respond to ancient threads.