electrical Problem 1977 450Sl
 

:confused: My 77 450 SL overheated and I have effected all repairs only to find out that the car developed a electrical problem. I have several issues found IE. the tach, fuel gages, turn signals, 4 way flashers, power windows and antenna do not work. I have check all the fuses both visually and replace a few but can not find the problem. Can anyone help provide me a place to start baffled and piss off

Hi there:

It doesn't sound like a fuse problem as you are describing systems using at least 4 different fuses on both the upper and lower row so you can at least rule a blown or badly seated fuse out. ( eg Windows are on fuses 3 & 4 and the relay for them is on fuse 5 plus the antenna is on fuse 12)

Sounds like a major wiring (loom/harness) fault, Did you "pull" or disturb an multi-way connectors such as those between the engine bay and the bulkhead when fixing the overheating fault - or could the wiring loom have been damaged either when it overheated or in the repair?

Happy fault hunting.

Cheers

Jim

I can understand your frustration. Trust me on that one. Start with one circuit and at the fuse panel. Use a tester. The kind with a light in it. If there is a short you will notice it when you touch the top and bottom of the fuse contacts because the light will light up.
Ask yourself this one question. when did these problems occur? Did they happen when you have the vehicle. If so what did you do. Did you rewire the 4 way hazard flshers?
I will tell you that the wiring loom is capable of taking a beating and will keep on ticking. In this case try not to make a mountain out of a mole hill.
Track the antenna first. disconnect the switch and check for power with a multimeter. If you have power then determine the wires going to the antenna. Check for grounding or corrosion going that way.
Power is affected through the 4 way flashers going to the instrument panel. Google "hazard switch configuration 450sl" Or something close. I had to. Someone figured out the wiring configuration to the hazards and BINGO problem was solved.
The fuse panel is color coded for amp rated fuses. Hard to look and verify fuses blown. Take a digital camera and get a couple of good shots so you can see clearly each and every fuse. You might be surprized to find out if there are fuses that might not belong in the correct slots.

look at your common grounds, one or more may have been melted?? How hot are we talking??

Electrical Problem
 

I would like to thank all for the information provide. The problem was really discovered while the car was overheating. I first saw the gages went dead while the car overheated. That is was I am trying to tie the overheating to a cause and effect problem. I have a Hayes book that describes a thermal switch/relay what is the function of thermal switch. My aux electric fan has never started also after repairs. I have purchase the fan switch but I can find the location of the sensor Help. And I will start looking for the ground this weekend. Keep the info coming I really appreciate

RafyR

Found the Problem Electrical
 

1977 450 SL
After not trusting my eyes and removing and checking my fuses with a fluke. I discovered that I had replaced a fuse with a under rated fuse and it blew again. I replace it with the correct fuses and I am back on the road runing. I would like to thank you all the help and motivation to keep going. I am looking for the help on parts

Looking for parts for MY 77 450 SL
 

During my last repairs a noticed that I need to replace a few body parts. I need both inner and outer fender for both sides. Along with lower front Valence. I also need the sun visor clips both for Bambu interior:o Any direction to a parts place that has reasonable price would help