I recently purchased an 89 190E 2.6 which has theft alarm (little red light by ignition switch). The car has a manually wired toggle switch near the console which appears to have been put in to try to disable the theft alarm, but its action is only sporadic. Can't ask previous owner as he has died. The alarm has "self activated" a couple of times (horn disabled, but lights flash, relays under passenger set click away). This eventually stops, but is quite annoying. Is there a safe (ie, doesn't affect anything else) way to disable the anti-theft system, preferrably reversible?