Hi all,
i have a 1992 mercedes benz 400se , have the following problems and i think they all related to each other,if you know the answer please let me know.
oil pressure reader is not moving at all ,( just did oil change, and checked oil level ) .
-horn is not working at all, checked all fuses ,all working.
-heat and ac unit does not work at all ,i can see the red light go on ,but i get no air what so ever.

please any help, thanks again