The subwoofer in my 99 EB works intermittently, and when it does work it doesn't sound quite right - but, thanks to the help of this forum, I've taken the speaker out and tested it on it's own and it works fine. It seems the problem is with the amplifier, so I thought I would replace it with a spare Yamaha amp that I have. However when I check the connections on the plug that I disconnected from the the factory amp, I can't get a solid 12 volts. The +/- supply wires read 11.5 volts when I put a meter on them, but when I connect them to my new amp (which works fine when connected directly to the batter) the voltage in the plug drops to almost 0. Has anyone experienced anything like this? It almost acts like a bad connection - like when your battery leads are dirty; they supply 12volts until you need some current, then you get nothing.

I'm not using the remote turn on lead for power - I verified by turning the radio on and off which one that is.

I appreciate anyone's help.

 

This is one of the oddest problems I've come across. I think I have only seen this once before.

I checked the wiring diagram and confirmed that I was testing the 12v power lead. It read 11volts w/ no load, but dropped to less than 1 volt when the new amp was connected (remote terminal jumpered to power terminal). Based on what I saw, it appeared to be either a bad ground or bad connection on the power lead. The wiring diagram showed a connecter at the front passenger seat footwell - I checked there and found 11 volts on both sides with the amp connected. So, it appears that somewhere between the connector and the amp, the wire is bad or corroded and not letting enough current through to power the amp.

To test the theory, I reinstalled the factory amp and speaker, cut the power lead wire on the amp side connector to leave 5" pigtail (disconnecting it from the wire harness, and connected a direct 12v source from the battery. The factory amp and speaker work fine again!

So, I'll now have to run a new wire from the front passenger seat kick panel to the amp and splice it in - not too much trouble now since I have everything tore up anyway.

Have you ever heard of a wire going bad?

 

It was the wire. I ran a length of 14 gauge wire, spliced it into the connector at the passenger side footwell (disconnecting the factory feed in the process), and into the factory amp. This was the 12v feed wire, not the amp turn on signal.

 

It sounds like you may have blown the fuse for the amp? A blown fuse may still show 12volts on a meter, but as soon as you put it under a load it drops off to next to nothing as you saw.

Mike

 

thats a new one to me, anytime I have came across a blown fuse it opens wide up and no voltage. It is what they are desighned to do.

check the ground, trace the old wire and see if there is any physical damage, there could be more problems on the way.

 

Had this happen with a hot water thermostat once (Home hot water heater). Was a pain cause everything tested fine but under load it wouldn't work. Just like you said when it would try to pull a load it would 'break' the circuit and when no load it would test fine. This can happen but never seen it happen in a wire. I'd think more of the connection at one of the ends. Glad you found it though cause wiring is the pita when it goes bad