My 2002 E320 did the same thing. The key fob worked and I could push in the trunk lock and it would open. When I did that, the red light on the console trunk button lit. I tried switching the hoses on the PSE pump under the rear seat and that did not help. My guess is that the problem was the switch under the console. I never fixed it. I think the switch under the console was about $400 or so. It wasn't worth it to me.The trunk release swith on the console stopped working. Even the light on it does not light up when the switch is pull. The trunk opens fine with the remote.