I have a 1990 240 DL wagon. Last week I had to replace the electrical harnesses that are in the back of the tailgate. Actually they are right underneath the back door hinges. I had not replaced the worn wires when needed and therefore ended up shortening out my alternator. Anyway my current problem is that when I turn on my headlights my rear window heating button lights up and stays lit until I turn the engine off. As long as I do not put on my headlights the the lgiht does not come on. I was going to remove the fuse - which is also tied to the overdrive but decided against it. I ended up disconnecting the bulb so that I would not have the light on whenever I drove anywhere at night. Any ideas what the porblem could be????? Most probably a short somewhere else along the main electrical harness or underneath the dash??? Thanks all for responding.