Just got this message from an1991 E31 850i owner: after shogun gave me a link to the wiring diagrams i was able to see terminal #7 on the crash relay was grounded so that led me to the hazards switch. i pulled apart the switch and found corrosion on the pc board that was shorting out. i just cleaned off the corrosion and put the switch back together (man that was tough because i have big fingers and there are tiny parts in there lol). it fixed the problem