I set my gain to 4volts (well i guess cuz the gain goes from 1v to 8v its set in the middle) anyway the clip light comes on is that normal or what and i read using the gain as a "volume Knob" can cause damage so what to do
Just because you're halfway doesn't mean that the gain is optimized for 4V, they aren't proportional like that. It will likely be well under halfway, closer to 1/4. What you need to do is get a 0db reference tone, play that at the maximum unclipped output of the head unit (or just use 3/4 volume), and set the gain to a level that the amplifier doesn't clip. An oscilloscope is optimal, but you could use the clipping light.
As far as oscillioscopes go, there not cheap and I doubt you can rent one but who knows maybe where you live you can rent one.
However a good solution is to get a PC based oscillioscope program that utilizes the sound card and has many of the same functions as a real oscillioscope. Just do a search on google for one. I downloaded one for free from i site i found on google. You use the microphone line as the input. You could get a 3.5mm jack and cut the wires and then wire that to the speaker ouput of the amp. Im not quite sure what kinda of power your PC sound card can handle though, so make sure everything matches up or you could be finding yourself buying a new sound card.
for real for real the i set gain 1/4 of the way so the light wont come so thats right then i guess but the alt,how can i tell if the alt is not sendindg enough current. i know this the headlights do not dim at all which seems odd for 500rms watts or 1000watss at 1 ohm that i had so will an amp just not pull any more current if it not there to get is it that advanced?????