I have a 96 E300D with an intermittent starting problem. The antitheft system won't allow me to start the car somtimes.I have had the key battery changed, new key, new ignition switch, new computer but hte problem still exists. A friend told me he had the same problem with his car and a new voltage supply regulator (210 5400 372) fixed the problem. Where is this part located on my car so I can give it a try. Thanks so much for any help.