My local library recently got a subscription to AllData, which I gather many shops use for service bulletins and detailed procedures on many cars. I found there and printed a pictorial list of all the ground connections on the 240. Very helpful.
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Jim (90 244DL 175K miles) turbo sways w/poly, front struts & bushings, OD wiring, downpipe, OEM hitch, remote-locks.

I'll second t-bone on checking the grounds. Some really weird things can happen when grounds go bad. In fact it's a good idea to go through your car and clean and tighten all grounds.

Alternator brushes been checked?

Was it your front or rear turn signal?

As T-bone suggested, check grounds to your tailights. Clean all corrosion in the area.

I would also check your tailight circuit boards for corrosion and/or damage. You can clean them, but if they are too far gone they might need replacement. That was the case with my 90 about 4 years ago. Replaced one circuit board and the bulb failure sensor unit and everything has been fine since...


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90 244DL 252K - original engine/drivetrain :)

I'd check the grounds to your tailights/brakelights. My 245 had a similar problem as the result of the high center brake light ground wire breaking in the tailgate hinge. I fixed the ground to that brake light and the mystery of the warning lights coming on with the application of the brakes was solved. Simple to fix if you find the bad ground. Hope this helps.