Audio Systems: my amp and my fuses, dodge grand caravan, watt amp

Question
QUESTION: i recently installed a 450 watt amp into my 1994 dodge grand caravan and when i turn the amp on while my lights are on it blows the fuse to my illuminators for the speedometer etc. and if i leave the fuse out i cant turn my radio up more than about half way before it turns itself off. so my question is what is causing my amp to use the fuse for my lights, why, and how can i fix it? thanks

ANSWER: Well, you have several possible problems.  Let me start with the most obvious.

ONE: The blowing of the fuse for the instrument panel would lead me to believe the amp is connected to the wrong circuit.  An amp this size should have its own fuse and the main power line should to directly to the battery.  The remote turn on line for the amp should come from the ignition or the head unit.

TWO:  The turn off when volume is increased is most likely one of the following:

a. speakers are too low impedance for the amp.
b. one of the speakers has a shorted voice coil.
c. there is a shorted condition somewhere in one of the speaker wires.
c. 12v line from the battery drops too low and amp cuts out.

THREE:  Wiring could be wrongly installed. Please go to this site to check out the wiring of this vehicle so you can check for crossed wires.

http://installdr.com/InstallDocs/DCP/PDF/327001.pdf

The wiring diagram is down at the bottom of this long page.

FOUR:  And, finally, it is possible there is an internal defect within the amp itself. You can pull it out and "bench" test it for proper workin.

If you need more, give me the make and model of the amp and the speakers you are connecting to the amp and I can be more specific about the installation.

Good Luck,
C



---------- FOLLOW-UP ----------

QUESTION: ok so i've checked the wires and they are all connected properly but the problem i've noticed now is that the illumination wire for my dash lights is the only way that my radio will turn on, i have the power running directly to the battery and the ignition turn on/off wire is also connected but my radio wont turn on unless the illumination wire is connected also. i have a sony xplod radio with factory speakers. my amp is a lightning audio along with the subwoofer that is 12"

Answer
That is because the radio is connected to the illumination circuit. That is correct in one way.  Why?

Here, think this through and then go back and check the wiring:  There are two power wires to the radio and maybe three, depending on the wiring scheme.

ONE: To the battery for powering up the radio.
TWO: Remote turn on of the radio.
THREE: This one is the illumination in the radio that allows the panel light on the radio to go up and down with the illumination control on the rest of the dashboard lights.

If you have these circuits crossed or wrongly connected it can cause the very problem you are having.

I think you have the illumination wire connecting to the wrong place on the radio unit.

So, please check it out again.

C