I am helping my sister out with her car audio issues. She replaced the original head unit with a Pioneer FH-X700BT due to a broken CD player. the installer used an Axxess GMOS-08 interface and the system worked OK. She started suffering dead batteries and the radio fuse was removed and that cured the issue.
Then she started hearing hissing and popping from the speakers even with the radio fuse pulled. Pulling the amp fuse stopped the hissing and popping so we believed the amp to be faulty. Since the FH-X700BT offers plenty of power on its own for her needs, we decided to bypass the amp. I bypassed the amp by cutting the speaker ins and outs at the amp, soldering and taping them. I also unplugged the amp power, subwoofer wires and cut and taped the amp sense and amp switching wires.
I re-installed the radio fuse and after the initialization period for the interface I fully expected great audio and all we are getting nothing unless we crank the volume fully. On the bright side, even with the radio fuse still in place her batter isn't being drained so the amp must have been the culprit all along.
I believe the radio is not putting out speaker level power but line level power to run the amp as controlled by the GMOS-08. I am inclined to cut the accessory wire coming out of the FH-X700BT and wire it directly to an ignition source.
Thoughts on where we go from here?
Thanks in advance your any help.
