In my 88 240 wagon, i have a fairly random issue with the Bulb failure light in the instrument panel. Sometimes it comes on sometimes not. Most of the time it lights up when I press on the brakes or turn on the headlights. I bought a few of the tail light bulbs and replaced the three brake lights. Passenger side and the window brake light were blackened slightly, but still working. I tried the search function but it seems to not be working. Does this seem like a ground issue, wiring issue? I was told by the previous owner that the wiring harness on this particular model doesn't have the deterioration of others. Unless he's a dirty liar, where would be the most probably places to clean the ground at?