ok hear it go's I bought my son a 88 s-10 blazer put a sound system in it, ams and all. some how he got the main hot monster cabel out from behind the wall and grouned it in the back seat latch it melted the 100 amp fuse but not the amp. ok i replased the cabel hear is wear it gets weard.(1) you can turn on the radio and the the amp and its fine.(2)you can start the thing at idel and play the radioand its fine.(3)you can drivewith the radio off and its fine.(4)but you can't drive with the radio on the radio keeps turning off when the amp gage hits about 9 head lights do the same blinkers and windshild wipers fluxuate the gage to but get this all this hapens when i put it in to gear stnding still is ok iv unpluged allmost every thing off the colum except for the turn sing loom and everything off the trans even the safty nutral switch any help will be gratly apresheated thank you

 

are you using a capacitor? what size wire is running to the amp and from it? over all (unless i'm miss reading) it sounds like the sound system is drawing too much electrical resources in wich casea an amp will definately help..... and make sure where it's grounded you have good contact, sand off any paint so you have metal on metal contact. i had my system grounded under the rear seats on my 96 with no problem except a little dimming when i had the sound cranked.

 

^^^^^^ and how many amps is that alternator pushing????? You might have to get a higher one. I think your stock unit is only like 60 amps or so. Might need to jump up to a 100amp alt.