Van Gogh very loud whimpering RCA OPEN???

Moinsen, when I started the ignition this morning An animally loud whimpering from the sub and the TMTs. I then took off the Cinch to the VGA and it was gone, again and it was there and it flashed the little lamp RCA Open, Cinch once exchanged, the same problem. In the description is the following, actually my English is so far good but that too much on the shock: “is illuminated if negative/ground audio reference point is ether” not securely connected or completely dis-connected. Note that selector switch must be in “sense” position the other two amps provide the FS perfectly. Link to descriptionDescription Click