I just purchased a 82 380SL.
It is in fine shape but I have a question that maybe this group can
answer.
When the car is running there is a whining sort of noise or maybe a
high pitched hum sound that is coming from the back of the car on the
passenger side in the truck.
Is this the fuel pump and if so is this normal.

Lastly the interior cabin light switch when turned on blows the fuse. Should I just replace the switch or do you think the short can be elsewhere.


Thanks

The fuel pump can and does usually make a buzzing or whining noise on most benzes after a while.

I know my car has a slight buzz, and my brothers 85 380sl also makes a buzzing and my fathers 1994 sl600 also makes a buzzing.

ohh and the 1987 560SEL that we used to have also made this same buzzing noise.

I think its pretty much normal.But I am not a tech, but this is pretty much how most benzes are from my experience

Alon

My '81 also buzzes from the fuel pump. Makes me think it may go out pretty soon. (then again, maybe not. Could be normal) There is a good article in the last issue of Star magazine on how to clean the pump in order to get a little more life from it. Use KEROSINE (sp) or DIESEL only. Sparks will ignite if gas is used.

Fuse blowing
 

Blown fuses are caused by a direct short (As opposed to an open short, where no circuit can be completed). If you remove the bulb from the circuit and the fuse still blows, you may have found your problem. There are, however; other loads on the same fuse, and sometimes people install their accessories on marginally fused circuits, causing any additional load to cause the fuse to fail. Overhead lights normally light when a ground contact is made such as the door switch, or the direct ground in the switch. Assuming a switch/socket assembly, the switch can be checked with an ohm meter: with no bulb in place and both wires disconnected, resistance between terminals should be infinity with the switch in either of the two on or single off positions. With a bulb in place and the switch in one of the on positions, resistance should be a few ohms due to the filament being a resistance circuit.

Removing the switch
 

I have not even looked at the switch yet but do they just pop out or is there some trick in taking them out of the console?

380 SL Questions
 

Hi Ed.

There's one other thing you might want to look into, if you haven't already, on your new '82 380 SL. The original timing chain on that model is a single row chain which is prone to stretching and catstrophic failure after a comparatively short period of time. When this happens, the valves will end up in a noisy death dance with the pistons. The only recommended solution by MB is to replace the single chain with a double row chain, which requires a conversion of the chain, sprockets, guides and the like with the double row version used on the '84 and later SLs. This is expensive (in the order of 25 - 30 hours labor, not to mention parts), but much less than the cost of repairing or overhauling the engine damage which will occur if the chain fails.

All that being said, your car may already have been converted - many have been over the years - so you may be just fine. Not all have, however; the whole issue was a bit of a mystery to me with my '81 until the chain started slapping on start up. If you don't know what type of chain you have, you can find out easily enough by removing the valve cover and taking a look.

Hopefully, this information will be old news to you. However, since it is a classic example of "pay me now...or pay me later", I thought I should bring it up.

Enjoy your new car.

Regards,

TJR

Reference the double chain conversion, I just finished with mine last week. Runs great, (so far...fingers crossed ;) )
If anyone is interested in my experience with this, give me a holler.

Thanks again
 

The car did have the double chain installed.
I read about this problem and would not have purchased one that wasn't already modified.