A buddy of mine just purchased a 18' Sea Ray. Nothing special - must be a 98/99. The aftermarket deck is a Jensen one (CD335X). The place where he bought it from couldn't get the HU to even power. After looking at the rat's nest of wiring, I found that an inline fuse was missing - that got me power and one tweeter work. I re-worked some wiring and got the second to work. The other speakers (I think there are only 2) must be 4" or so and wouldn't work at all.

Here's my question - I tried all the outputs/channels(?) and only the two work (purple and grey). The green and white won't. Any reason why? FWIW I took and tried to fire the tweeters off all 4 outputs and only those two worked. I normally would just scrap all the crap and buy new/re-wire it the right way but he's a cheapazz. Would it be the HU or the wiring harness? I'd assume the HU as I don't know why the harness could be "bad".

BTW this same place couldn't get the horn to work - again, it needed a fuse (blade type on fuse block). Wow...

 

Sounds like those 2 channels might be bad if you tried hooking the speakers you know work up to them. Time for a new deck.