Bypassing a multi function Christmas light string controller
This "should" work.
2 transistors are driven by control IC.
Connections as shown shorts transistors. 



That's about as nice a set of photos as I've seen with a question.
A welcome change.
Sharp, well lit, shows area of concern.
Leads were initially not 100% clear but once my brain engaged (5am - up to shake off a nightmare :-) ) it was clear enough.



Why is the left hand common lead +ve and not -ve?

And even rougher :-).
Here is why the lh trace is +ve.
On the copper side image all diodes "point right" - diode cathodes right.
So, if AC goes to an Anode the Cathode is DC positive.
If AC goes to a cathode the anode is DC negative.
In this case the 1st and 3rd diodes from the top have the AC input connected to their Cathodes (rh side/ bar end in copper view) 
So their Anodes are DC positive and are joined together and have a trace running to PCB bottom left - which is thus DC positive.

A multimeter set to volts will confirm this.  

Presumably (he asked again) there is an AC transformer and AC mains is NOT connected directly to the PCB.