Why do you have to run the stereo alts through the pcm ? Cant you just wire them completly bypassing the truck wiring ? I know our trucks are different but mine are all GM 4 pins but I only use two wires out of each plug ? One wire to ignition source to turn them on and off and other wire to battery to sence voltage to turn on and off. I dont know if yours are two pin plugs and may need the pcm to control them ? Probably would have been much easier to get four pin alts for your stereo alts and wired them direct. I got no problems with mine in fact I had used diodes on sence wires to keep them charging up to 15v and now with the Taramps that was a worry so I just replaced diodes with fuses and shes back to 14.4 charging and all is well. You might hit up DJScrubs on caco as he has a newer tahoe with multiple alts and alot of alt knowledge.
And why not one of these
SPL Meter under $200 atleast you will know where your at or close too it ?
