Ok, I am trying to install an amp and subs in my bro's Tahoe, with the stock head unit. I ordered a high to low line converter off ebay. It didnt work, thought it was the piece so I returned it for another one. Same problem so I ordered a different model. A Pheripel SVENR, but still no output. I am sure the speaker wires are wired correctly. I even tried wiring them up right behind the HU. And I know the wires are lives, because I hooked them straight to the subs and got high-output. But when wiring up the Preripel and the amp, I get no output. The amp does work, it was just pulled out of another truck of his and worked fine. The green ready-light comes on also. I cant think of anything that would cause this. I am either forgetting something completely obvious, or there is something that keep this from working in Tahoes. (I have installed the same converters in my car and my other bros car and they worked). Any help would be greatly appreciated.