I have a 92 190E 2.6 and I just replaced the radio with an aftermarket unit. I did not cut any wires during the installation as I will reinstall the original radio upon selling the car. However, after completing the installation, I noticed that the dash lights stay on and the auxiliary fans cycle on and off and the right side rear parking lights stay on when the key is removed. I pulled the center part of the dash out again to make sure that I hadn't cut or shorted and wires, but couldn't find anything obviously wrong.
The only other thing I could think of that would be a possible source of the problem is that I degreased the engine earlier in the day, being very careful with the water stream. After hosing off the engine, I drove the car for several miles, then had lunch. At that time, the car shut off normally and thee lights went off when the key was removed.
Additionally, the car has a Viper 600 HF aftermarket alarm installed on it that hasn't been a problem since I bought the car. In trying to narrow down the source of the problem with the lights staying on, I unplugged the alarm control unit, but the problem remained.
Do you have any suggestions? I appreciate any help you can give me.
I would begin by looking at the various electronic items under the hood. The was down was a bad idea and should not be done on these electronic vehicles. Try taking a haid dryer and hitting all the relay boxes and electronic controllers.
Sounds like you did lots of things at once, and one of them will have caused the fault(s) (probably)
1st thing to do is to disconnect the radio (unplug all the connectors) and see if the fault remains. If it does, its not the radio, then you can address.
Remember the radio wiring has a permanent positive, a switched positive, a lights on feed and a feed for the power antenna, possibly a mute signal etc - if these are connected up wrongly then all hell can break loose.
If it does remain, then sadly its probably the water in the engine bay which may be a lot harder to find what is shorted - however, you need to start looking in the area of any fuse box which will have relays to control lights, auxiliary fans etc etc
The alarm (to me) seems unlikely to cause all that trouble, its unlikely to be connected to the lights etc ..
Thanks for the ideas. I started by removing the relays 1 by 1 and brushing the terminals clean and sprayed terminal cleaner in the sockets. After 15 minutes of work, the problem was solved. Car is now functioning normally while still allowing me to enjoy the new stereo. Thanks for the ideas.