77 450SL electrical problem.
 

Hiya folks,

I finally got my 450SL smogged and registered. (It don't want to talk about smogging it...it did not want to get through).

Now on to the next problem. The car seems to have a temper and , it eats the battery if it hasn't been driven in a week....lol. OK, maybe it's not a temper just and electrical problem.

I poked at the fuses and found 1 and 2 hot with car off and doors closed. Seems that 1 should be hot at all times...and in fact required for car to run. 2 however does not seem to affect the car when removed (at least setting still).

Since all I have is a chilton book and no fuse box panel at the moment can someone inform me of what fuse 2 is used for (top left). Or does someone have a diagram thay can send?

appreciate the help...

I am betting my '75 450SL has similar fusebox to yours...on her the #2 fuse reads on cover panel:

clock, standing light r and l, trunk light, warning buzzer, entrance, lights glove compartment light (automatic antenna)

hth

Might be...
 

That might be it. Clock would explain it. My first thoughts on battery drain are always clock and radio. Chassis electrical on 74 - 79 (maybe 80) are very similar.

If that is all it does, I'll remove the fuse and see if I still get the drain. If not I'll start tracing.

One question..what is a standing light?

Thanks!!!!

Spoke too soon. Looks like warning buzzer, entrance light, etc are hooked to my #1 fuse (bottom Left) according to electrical diagram #1 should be turn lights? Ok Now I'm confused.

Still not sure what #2 does.

Numbers behind fuses look like this left to right:

2 4 6 8 10 12 16 18 20
1 3 5 7 9 11 13 17 19

from 77 450sl wiring diagram
 

attached image is a screen capture of the portion of the 77 450sl wiring diagram that lists the fuses....should have looked it up in the first place instead of assuming it'd be the same as my 75's fuse layout

Oh thank you...I'll print it and put it in my book and my car!

I think I can do without an auxillary flag for now don't you?

:D

Umm "fan" rather.....

I don't know about that...I believe the function of an auxiliary fan is to cut on and cool down the radiator/engine when it goes above a certain temperature...for instance, mine cuts on at above 200 degrees when on the highway when engine temps get above the normal of 175.

hmmm...well actually I'll leave the fuse out for a week and see if the battery run down while it sits.

Hubby gonna do the Amp meter thing (I did volt) and see if he can find anything else. Now that we have the fuse chart it will make it much simpler to find.

Thinking about it it would make good sense for that to be live. How else would it cool down the car after you turn it off?
...lol

No weird amps..sigh...

This thread reads like a drama, and it unfolds a plot on who dunnit to the batteries.

My guess would be to first check the reliability of the battery, i.e. new or old and whether the battery itself is the suspect. The clock - dead or alive, won't take much of the battery life unless it runs on full digital with the complete Big Ben chimes built in.

If battery is fine - then we start looking at Amp thieves or smugglers.

Hope all would end well.

:)

2 days in the garage
 

... and the battery's flat.

Now the 300SE is in the workshop checking on the battery which is under warranty.

Talk of coincidences.

Something must have drained the power.