76 2.0, was driving today and my fuse box relay board under the dash started smoking! I got the car home and pulled the fuse board down to find the far left relay's yellow wire into its base was melted. I believe this is the horn relay, and the horn doesn't work now. How do I get another base to replace the melted one? Btw, the car would not shut off with the ignition switch after this, I had to pull the coil wire to stop it. Is this a coincidence to the melted horn relay base wire, and what is that telling me? HELP!
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Click to view attachment

Put a WTB in the classifieds
Pretty sure you'll be able to get one. Then just a matter of splicing it in.

Did you unhook the ground from the battery? It's been my experience some of the yellow wires are unfused from the battery.

Click to view attachment
The 75 schematic doesn't show a yellow wire in either the horn nor the blower relay.
Can you see the pin numbers molded into the socket? If so can you list which wires go to which pin number?

I wouldn't start cutting yet. I would pull the ignition switch and inspect for damage. Sorry to say you have a short somewhere and its probably not just in the relay socket.
If we can figure what socket it is I can probably cut one out of a spare harness that I've been cutting wires and sockets off of.

My mistake, the melted wire is red w white stripe. Other 3 wires are brown, red, and rd/black. Does that help ?

Yes that is the fresh air blower relay. The red white goes to the headlight switch. Which is tied/spade terminaled together with a big red wire on terminal 15 on the headlight switch. The big red wire travels to the ignition switch to terminal X.

Before you fix the melted switch, find the short. Otherwise you will melt another one.

I have a few scrap harnesses that could be used for a donor.


PM me if you want it.

I know the standard fix for old Mercedes blowers was to wire an in-line fuse holder into the circuit so you could put in a larger fuse. As the blower motor ages and the brushes wear, it will pull more current. maybe it's time to pull the blower motor, check the brushes, and clean things up a bit.

I always thought this was a band-aid fix, but many an old Mercedes was built by hanging the blower housing by a string and building the car around it. Replacement of a blower motor was the reason for scrapping more than one...

Gary

[quote name='ClayPerrine' date='Nov 9 2016, 07:46 AM' post='2420948']
Before you fix the melted switch, find the short. Otherwise you will melt another one.



100%,make sure you solder the joints when you add in a replacement relay base, seal up the joints with glue heat shrink then you know its done right.
Sounds like you melted your ignition switch also,you certainly want to check that.
Good luck,sounds like you dodged a bullet here could have been a lot worse .