i have a 1993 500sl with 79k miles and it has been having some electrical problems


on the fan control panel some buttons dont work anymore, the temperature is stuck in celsius and the rest button just causes the screen to be garbled untill i release the buttonm, a few other buttons dont work as well

the replace headlamp warning comes on often as well, i have the lamps replaced and after a month the warning light comes back on and the left bulb starts to dim

 

It seems you may need a new AC control module, can be quite expensive. Maybe you can find a used one, or have your old one fixed. Its fairly easy to remove, just push it out from the back. You can remove either the radio or the A/C vent above the control unit to have access to push it out from behind.

The wires and connectors for the headlight may be damaged or corroded, remove the plastic cover behind the headlight and look carefully. Unplug connectors and check for breaks and corrosion.

 

would corrosion cause the bulbs to burn out quickly?

and where could i find a replacment a/c control unit?

 

Im not sure about corrosion causing the bulbs to burn out quickly, but the light may be getting dim due to insufficient power going to the bulb.

You should be able to get an new control unit at the dealers or any place that sells MB parts. Or you can check at the breakers for a used one.