The radio volume was about 10% at full radio volume. After about 15 minutes the volume would go up about 20% if set to max. I have an aftermarket radio installed into the factory system. From research I had checked the wire connection on the passenger side rear door and it looked good. I also tested the the rear glass antenna as that was listed as a possible problem. I used an aftermarket external antenna and no difference was noticed in the volume of the car's system. The amp is a Panasonic Mod 10449235. I bypassed the factory amp per a post on the internet and the radio worked fine. The problem was my factory amp.