Anyone know why number 14 fuse is blowing every time the key is turned on?

Last few days I really could have used a horn, especially today!

I have tried unplugging the auxiliary fan and the mono valve, but now just too frustrating without help...


Thank you all in advance!

__________________
Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

Here is what I would do.

Go to startekinfo.com, select MB Workshop Resources on the left, page through until you find the 123 Workshop Manual.
In there is the wiring diagram for the car.

Get a light socket with an 1156 brake/backup/turn signal bulb in it, either from a parts car or a new generic one from the parts store. Using a couple alligator clip leads (Radio Shack), attach this in place of the fuse.

The light will glow brightly if you have a short circuit. If you do, here is how to find it.

Disconnect the battery - cable and remove the lower drivers side dashboard cover. Remove the fuse box cover, and remove the nut and washer holding the frame of the fuse box into the firewall. Go back inside under the dash and carefully lower the fuse box to the floor. There is enough slack in the wires to allow the fuse box to lay on the floorboard.

Hook your light bulb back up, put the battery - cable on (loose is ok at this point) and see if the bulb is still glowing. If so, remove the battery cable, flip the fuse box over, and look at the back of fuse #14. There should be several wires under the screw on the load end of the fuse. Remove the screw, and take one of the wires off, and put the remainder back on. Put the battery cable back on, check with the light bulb, see if the bulb is not glowing. If so, you found the wire with the short in it. If not, put that wire back and try removing one of the other wires until you find the one with the short.

Now using your diagram, find out what is on that circuit. Start tracing down the circuit to see what devices might be causing the problem.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Thank you so very much Jay Bob for the reply! I will print it off when I have a day available. Though, hope I don't have to touch the fuse box, as last time I did that didn't work out so well...

__________________
Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

The Haynes manual says fuse 14 powers the horns (duh!), NSS and kickdown switch. Disconnect the kickdown switch at the end of the throttle pedal travel then see if the fuse still blows. If so, reach under to disconnect the NSS then try the starter (it won't engage) to see if the fuse blows.

Sixto
87 300D