I dodged a bullet monday. The serpentine belt that drives the water pump and alt. broke. 580SL was in the red on temp guage for no telling how long. Any way i put a new belt on and it is ok. The #26 "Engine Temp Switch" It is supposed to trigger the #25 "Warning Alarm" and it did not. Alarm is working on other things. Looking at the wiring diagram. I guess the #26 ETS gets its ground from the engine and when it senses high temp it grounds and sends ground signal to #25 warning alarm right? Well when i take wire off of ETS and ground it alarm does not sound. Where do i start looking?
Replace the sensor/sender.