Line out converter

Howdy. I just bought a Blaupunkt Sanfrancisco 320 for my little VW. It comes with 4 preamp out (front and rear) plus a "Sub out" and "Sub out GND". I am going to run the sub out through a line out converter to my amp. The LOC comes with 4 wires to attach to speakers, so should I connect left or right (one channel) to the LOC? Or should I connect both left and both right to the sub out on my deck?
OP,I'm sorry but I don't follow...If the new deck has PreAmp Out why do you need a converter to interface the amp?
 Are the 4 wires on the converter speaker wires OR RCA terminated?

Sorry, deck has 2 channel rca outputs (front and rear) but also has a sub out (in the wiring loom). I am planning to use the rear preamp outs for rear speakers and don't want the woofer controlled by the front speakers. The converter is 4 speaker wires in and 2 rca out (to amp). The deck itself has built in gain and frequency controls for the "sub out". 
If the "sub out" is a speaker level output, you can connect one channel (left or right) to LOC.
If the "sub out" is a line level output ( I think it is ), you can connect the "sub out" directly to the subwoofer amp input without using a LOC.
Ok got it...
Doesn’t sound like you need the convertor any longer...Deck has direct couple to amps via Pre Outs & Sub out with crossover controls is everything you need..
Basically you have 2 full range signals passed via the PreOuts & a separate signal feeding the sub at whatever crossover have set..