daytime running lights mod

What exactly are you trying to do?  There are different definitions for DRL.  Do you just want the head lights to come on whenever the car is on?  Or do you want the headlights to come on at reduced power whenever the car is on?  Or perhaps use fog lights for the DRL?

If you just want full power from the head lights or the fog lights that is pretty straight forward, you'll just need a relay.  If you want reduced power you'll need custom electronics (usually a PWM circuit, but could use a lower voltage regulated power supply).

Wire a relay coil (pins 85 and 86) between the cars igniton and ground.  Wire pin 30 to a fused high current power source (like the battery, or the current head light feed).  Wire Pin 87 to to the head light hot feed.  If your current system has seperate fuses for each headlamp then just use two relays and keep them seperate.

If you want the system to shut off when the ebrake is on wire the ebrake on switch (should be a (-)) to pin 85 of an additional relay.  Wire Pin 86 to the 12vdc ignition feed above.  Wire pin 30 to ground and pin 87a to the ground of the relay(s) mentioned above. 

Install a diode across the coil of each of these relays used.

Basically, when the ebrake is turned on it will cause the relay to switch positions, thus preventing the ground signal from reaching the DRL relay(s).  When the ebrake is off the ground signal will pass through the relay and make it to the DRL relay(s) allowing them to work.