The relay in our chassis model is under the left hand dash panel rather than on the inside fender of the w123's. I have decided to replace my entire glowplug system with the newer pencil type glow plugs, and have purchased a kit that allows you to completely bypass the old relay and control the glow plugs with a manual switch. I'll keep you updated as to whether or not this fixes the problem. You can check the kits out at **************.com under the diesel specific parts.