I need a schematic for the Harbinger V2115 600 watt powered speaker

It could be a number of things. Does the head light up when turned on? Are the controls on the channel turned up? Is the master turned up? Have you checked continuity on the cables? Have you tried the speakers with another amp, or the amp with other speakers? This will help narrow down the problem.

Maybe an open ground somewhere or something needs shielded.

probably shorted the integrated amp chip...they are not worth the trouble to fix..buy some good equipment.

measure it with a fluke or similar multi-meter

If you do not have training in electronics you can cause serious damage to yourself trying to fix this. You will need to take this into the shop.

Where can I buy a horn for my speaker?

If there are stereo effects , like chours and delay it more than likely has 2 90watt amps

Here is your schematic for the power amp. There is a separate amp for the tweeter using a LM3886 which is fairly well protected. Open the unit and test the tweeter driver.

http://elektrotanya.com/behringer_b215a_power-amps_psu_sch.pdf/download.html

Scroll down to "Get Manual" and click on it to download the schematic. At the site is also the preamp section as a separate schematic. You probably don't need that for the failure you are seeing. A lot of the tweeter drivers seem to get blown up, but once you test you will be able to find if the problem is in the amp or the driver.

Likely the power amp has shorted to one rail... DO NOT attempt to use it as it could be sending high current through the speaker causing damage. Age of the unit doesn't have much to do with it. Take it in for repair. Unless you are electronically adept and can get a schematic this is not DIY.

TRY E-BAY.