Service light comes on and headlights turn off

There's this website www.reliable-store.com
They have books on ALL vehicles.
it covers wiring diagrams, electrical diagrams,
fuse diagram, torque specs, PCV, error codes, fault codes, service info,
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I have 1987 toyota 4runner model and I keep servicing and when needed repair it on my own. worth it !!!

This light comes on when one of the systems it monitors has a problem. If you reset it and it comes back on, something needs attention. Usually a burned out bulb will keep the light on. Check all headlights/park lights/and brake lights for proper operation. If no lights are out, the system will have to be scanned for problem areas with a scan tool and then the light reset

BCM see other post on it and the clock spring.

This could be either the clock spring in the steering column or it could be the body control module. The BCM. They are about 80 dollars USED.

I usually open up the headlight switch and look for a melting harness first. Then remove the switch and test for continuity. If all is good look for a fusible link. But your search usually ends with the switch

The service light tends to come on when there is a burned out light usually a headlight high or low beam. Would check the headlights an see if one is out.

sounds like you are having a short circuit, my guess is something in your ABS unit has failed, if it were me and ANYTHING AT ALL was happening that should not especially with something as important as the brakes on your car, i would get it serviced immediately, you probably shouldnt even drive it to your mechanic but get it towed there instead. any trouble that is brake related is a serious issue.

First... Read your owners manual - page 226 - Turn the ingnition switch to ON (do not start) and fully depress the accelerator pedal slowly 3 times within 10 seconds and then turn the ignition switch to OFF position.
Good luck and keep me posted.

that model of mercedes did come out with daylight running lights meaning that when the key is on the headlights come on at a lower wattage. and if your bulbs keep blowing i would have the wiring checked out.

Probably something shorting out. This is something that probably isn't going to be easy to figure out. You need someone that can diagnose it in person