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[BluBike]

I have a J & M amp and speakers that I installed  about 4 months ago. I had a few issues with the speakers and J & M was very helpful and sent out speakers even before I returned the bad ones to them. I recently had the steroe stop playing completely so I opened up the fairing and did some trouble shooting. The stock speakers would not play with the amp so I bypassed the amp and the J & M speakers played fine so the tech at J & M said to send the amp and speakers back as the speakers must be bad and putting the amp into protect mode. I wasn't thrilled with removing everything and putting the stock speakers back and then re-installing everthing once I got the amp and speakers back from J & M so I put a test light on the amp harness at the fairing end and I got a dim light. I grouned the negative on the test light to the frame and the light got bright so I put a meter on the harness and I got 12.9 the same as the battery. I used jumper wires from the battery to the input of the amp and everything worked fine so I started looking at the harness. When I initialy installed the harness I put the ground for the harness to the frame as the negative on the battey is quite full with heated suit, battey tender and trailer hitch wires. So I put the negative for the harness on the battery and everything works great, my question is if I had good voltage at the harness but a dim light I had a insufficient ground but why full voltage? I'm not understanding how you can have the dim light but correct voltage. Thanks in advance for reading this long post and helping in my confusion.

[hdbrad03]

It only takes one strand of wire to carry the voltage but you need all the stands to carry the current needed to power the AMP.

 


   Brad

[Jerry/MD]

BluBike,
The fundamental difference between the light and the meter is the test light will draw current...the voltmeter won't. I suspect you have a bad connection. When you attach the light a voltage drop is developing across this 'high resistance' giving you the dim indication. I would check both the positive and negative connections on both ends of the harness. I would also disconnect from the battery and measure the resistance on each wire.

Also, it is highly recommended on any amp install that you connect the negative wire to the frame, not the battery. Ignition noise in the stereo is a common problem when connecting directly to the battery.

Jerry

[BluBike]

Jerry,
Thanks for the reply. Once I connected the negative to the battery the amp powers up and the stereo plays well. I'll move the negative to a better ground on the frame and check it again. I haven't heard any ignition noise as yet but I haven't played it much since I connected the negative straight to the battery though. The positive gives a normal light once I put the negative straight to the frame bypassing the negative wire in the harness so Iit seems as if the negative wire was the issue.
I appreciate your help, Gene