Well fortunately my SL had the same style hazard switch, because the '87 TD is completely different. Anyways, did some "swaptronics" and it is indeed the hazard switch that was causing the faulty turn signals. I took the SL's out, plugged in the '83TD's and the SL's turnsignals wouldn't work. Put the original hazard switch in and they worked. Put the TD's back in, they didn't work. So I left the bad hazard switch in the SL and put the good one in the TD. Now, here is the interesting part. It being so nice out today, I drove the SL, and the turn signals worked fine. And no, Ididn't mistakenly put the bad switch back in the TD, because I checked. Well, I am sure it's temporary. I'll buy a new one anyways.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member