When the headlights are on is there an indicator on the dash that lights up on a 1989 Mercedes 560 SL?

If you're asking if there's a specific light that comes on the instrument panel when you turn your headlights on, the answer is no. The instrument lights will come on, as will certain other instruments such as the gear idicator, heater/ac panel, radio, etc. as you already know I believe on the 89 models, there are a cluster of idiot lights beneath the instrument cluster. One of those lights will come on if you burn out a headlamp or other exterior bulb. Basically, it senses too much juice in the system instead of powering a bulb...sort of works opposite of some car alarms that sense a drop in voltage when a door is opened, setting off the alarm. I recall years ago when a few Italian cars would have a "lights on" indicator light, but they found out they were useless, especially when that little bulb kept burning out. This was long before LED's. I hope this answers your question, and it's been helpful. If you're asking if there's a specific light that comes on the instrument panel when you turn your headlights on, the answer is no. The instrument lights will come on, as will certain other instruments such as the gear idicator, heater/ac panel, radio, etc. as you already know I believe on the 89 models, there are a cluster of idiot lights beneath the instrument cluster. One of those lights will come on if you burn out a headlamp or other exterior bulb. Basically, it senses too much juice in the system instead of powering a bulb...sort of works opposite of some car alarms that sense a drop in voltage when a door is opened, setting off the alarm. I recall years ago when a few Italian cars would have a "lights on" indicator light, but they found out they were useless, especially when that little bulb kept burning out. This was long before LED's. I hope this answers your question, and it's been helpful.