I am having a very confusing time figuring out what is the problem. I got in my car and only the rear speakers work because they are off of the headuint; the front speakers and the subs are off amps. I measured the voltage of the battery + to a ground off of the battery and it was getting 12V exactly. i go to the other end of the fuse that leads to the rear trunk and it gets 12 volts. when i go to the power wire running in the back, i get less than one volt. i have a 4 gauge wire running to the rear of my car, is there any idead what may be going on? I got home from work 2 hours ago and everything worked fine but now it doesnt. any info would be helpful

(by the way, the car starts fine and the cd player works fine)

 

.....so....where is the voltage drop?

Anyways, trouble shoot the amp and see what is going on there, make sure the grounds are good.

 

Are you touching bare metal on the other probe on your meter? Have you checked the continuity of the ground wire to another reference point (somewhere else on the chassis?)

 

Is this what your doing/getting?




If TP3 reads something like 0.200mV or smaller and varies alot, then chances are your just picking up noise, and not actually any real voltage level.

If the above is correct, then sounds like your break is somewhere along your fuse -> amp. Since referencing TP3 correctly would still read 12V from before the amp.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imadigitalgod &raquo;</TD></TR><TR><TD CLASS="quote">I am having a very confusing time figuring out what is the problem. I got in my car and only the rear speakers work because they are off of the headuint; the front speakers and the subs are off amps. I measured the voltage of the battery + to a ground off of the battery and it was getting 12V exactly. i go to the other end of the fuse that leads to the rear trunk and it gets 12 volts. when i go to the power wire running in the back, i get less than one volt. i have a 4 gauge wire running to the rear of my car, is there any idead what may be going on? I got home from work 2 hours ago and everything worked fine but now it doesnt. any info would be helpful

(by the way, the car starts fine and the cd player works fine)</TD></TR></TABLE> if you had the circuit loaded, (IGN on)you should see about a 1/2 volt AFTER the load (amp in this case). you would be checking from the negative side of the amp, where the ground wire just exits the amp. Put your + meter lead there, and your - lead to ground, any spot of the chassis without paint. your gauge larger gauge wire won't cause voltage drop alone, if it is in good shape, but you may have alot less resistance. you can check it using ohms on your meter. shouldn't be a factor for voltage drop. make sure you put your meter on direct current volts, VDC for the first test. trace back from the amp towards battery and find where your 12 VDC is going. Make sense?

 

Check your grounds and connections also... sometimes the little things are overlooked.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imadigitalgod &raquo;</TD></TR><TR><TD CLASS="quote">I am having a very confusing time figuring out what is the problem. I got in my car and only the rear speakers work because they are off of the headuint; the front speakers and the subs are off amps. I measured the voltage of the battery + to a ground off of the battery and it was getting 12V exactly. i go to the other end of the fuse that leads to the rear trunk and it gets 12 volts. when i go to the power wire running in the back, i get less than one volt. i have a 4 gauge wire running to the rear of my car, is there any idead what may be going on? I got home from work 2 hours ago and everything worked fine but now it doesnt. any info would be helpful

(by the way, the car starts fine and the cd player works fine)</TD></TR></TABLE>What kind of fuse is it? If its one of them POS glass ones relpace it , it may look good but it may not be, I replace at least 2 of them a month at work , they have a lot of resistance and will get very hot when cranking the system , hot enough to melt the solder that connects the fuse filement to the end caps, so it still looks good. 94

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fcm &raquo;</TD></TR><TR><TD CLASS="quote">What kind of fuse is it? If its one of them POS glass ones relpace it , it may look good but it may not be, I replace at least 2 of them a month at work , they have a lot of resistance and will get very hot when cranking the system , hot enough to melt the solder that connects the fuse filement to the end caps, so it still looks good. 94</TD></TR></TABLE>

yup, replace the fuse. No brainer there if you get a drop after the fuse.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr_dc2 &raquo;</TD></TR><TR><TD CLASS="quote">

yup, replace the fuse. No brainer there if you get a drop after the fuse.</TD></TR></TABLE>NOPE&gt; Wrong. If it is the fuse your meter would read OFL-offline. unclosed circuit. If you have voltage, at all, the fuse is working. a fuse is on a 'go, no go' system.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fu*kfaceC1EH2 &raquo;</TD></TR><TR><TD CLASS="quote">NOPE&gt; Wrong. If it is the fuse your meter would read OFL-offline. unclosed circuit. If you have voltage, at all, the fuse is working. a fuse is on a 'go, no go' system.</TD></TR></TABLE>
Maybe if you were doing a continuity test. It would just show 0.000 if your measureing voltage.

My guess is your ground point or a blown fuse.

Also check where the cable connects up near the battery make sure you have a good connection.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fu*kfaceC1EH2 &raquo;</TD></TR><TR><TD CLASS="quote">NOPE&gt; Wrong. If it is the fuse your meter would read OFL-offline. unclosed circuit. If you have voltage, at all, the fuse is working. a fuse is on a 'go, no go' system.</TD></TR></TABLE> NOPE &gt; Wrong, a fuse that has a bad connection inside ,[at end caps] can show 12v without a load, and then show 0 to 12 volts with a load. I have replaced a lot of these glass fuses, most look and test good but they are not, replaceing them solves the problem, not to say that this is the problem here, but if you read 12v befor the fuse and less after the fuse it is the place I would look at first. 94