Since your led board works with 12 volts, i would suggest to use an optotransistor as TLP504 to accomplish your goal.
Just Connect the two emitters to ground and the two collectors to signal1 & signal2. The diode side will be controlled via your pic using e 330 ohms resistors on both diodes. Turn on the pic pin where you connected the diode and the corresponding NPN optotransistor will ground your control signal input. Mind you totaly isolated from the 12 volts.


Cheers

Al.