I'm trying to install a power acoustic 240w 4 channel amp in in a ford with sony(low grade) HU. I have power running to it, and i'm trying to run to 6x9 speakers of two of the channels. the problem i have is that i can't get sound out of the amp. i know it's not the amp bc i have two the same amps and i can't get sound out of either of them. i have the RCA running out the rear out on the HU and i'm only running the RCA's to two of the channels. What's wrong? Do i need to have RCAs running to all 4 channels on the amp or is there something else i'm missing. Thanx for help. latta. [email protected]