constructing a nand gate

I have a honda crx that uses two wires for the turn signals and two for the brake lights and I want to convert it to 2 wires so that the brake lights signal my turns. I know a NAND gate would do this but I don't know how to construct one or if I can construct one using relays.

What are my options? 

this should perform the NAND function, you may want to add diodes its your call...

I don't think that'll work.  IN-1 sends a 12v signal. 

Basically this is what the truth table would look like for what I need:

X Y | output

0 0     0

0 1     Y

1 0     1

1 1     Y          

Where X is a 12v brake signal and Y is a 12v turn signal. The turn signal can also be viewed as a clock signal. 

ohh man your right I drew the diagram wrong that common 12V on the coils is supposed to be ground.. ugh I dont know what I was thinking.

I dont understand your truth table what are Y outputs?

Ya when I was simplifing the logic I could use the NAND but for the circuit I need something that closely resembles an OR

XY  output

00    0

01    Y (just output whatever Y is, which would be the turnsignal)

10    1 (brake light signal)

11    Y (if I'm applying the brakes while signaling a turn I want to output the turn signal) 

Where Y is the turn signal output

hopefully this is more clear. I just want my brake lights to signal my turns.

K-map it

Alrighty,

Adding the third term makes way more sense; thanks JasonL.

And I see what you mean for the spdt relay. All I need is to find a wire that has a constant 12v when I've initiated a turn signal.

 After ploting the k-map I get

x(y)' + yz     but I this still leaves me with the task of finding the constant 12V signal that's mentioned above.

Well I can see the light now,

model x wrote:

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x(y)' + yz     but I this still leaves me with the task of finding the constant 12V signal that's mentioned above.

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talk about over complicating things...... could anyone possibly try to explain this in a more complicated method than has been done thus far?  why is it that it cannot be simply stated (the goal) like saying, "my car uses seperate turn signal and brake light bulbs, and i would like to consolidate all the signals into a single output circuit for each side, how do i do this?"  -- that was only an example, since i already know how to accomplish that circuit (and any other automotive circuit actually).... i'm just saying why not make it simple.  a nand gate logic looks like this:

and it works like this:

now, why you would want a light on when the input from both turn signals and brakes are zero is totally beyond me....  i'm guessing (because i have to due to the way your question was asked) that what you're really looking for is an XOR circuit ... which works like this:

either of those should be pretty easy to make from relays, but it helps to know for sure which / what you need first.

Hey chuckles if you read the first post you might notice where I state what I want to acheive, "I have a honda crx that uses two wires for the turn signals and two for the brake lights and I want to convert it to 2 wires so that the brake lights signal my turns".  If you already know how to solve my problem why have you not yet demonstrated it? even after the problem was already solved.

I know that I just need the input wire for the flasher, so problem solved.

thanks