This is my 3rd time posting on this subject. I have tried several things that were suggested on this forum to no avail. My problem is the #15 fuse on my 500sel. (1985 w126) It blows instantaneously when I insert a new fuse. This fuse controls the following: all door lights, both top dome lights, trunk light,power antenna, door chime alarm. I have disconnected all of the wires to the trunk switch, all of the wires to the power antenna, took the bulbs out of all of the door lights, (by the way, I have no crushed lights as someone suggested). I am running out of options. I don't want to take my car to a dealer and pay their premium labor to track down this elusive problem. There has gotta be something missing here. Thanks in advance.

Check the left side hinge for trunk light wiring usually that wire cause problem.

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner

I checked the hinge wires this morning for chafing, plastic wear etc, and can see nothing. When I disconnected all of the wires to the switch doesn't that mean that there is no power going to the trunk switch at all? Any more suggestions?

Have you tried disconnecting the wires from the connection at the BOTTOM of the fuse box on that fuse??

There is most likely a bunch of red/white wires there...you may need to de-solder or clip (give yourself enough room to reconnect them) 1 at a time to find the shorted circuit. whatever circuit that is shorted won't work.

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M.B. Doc,
I don't think that I can handle the disconnection of the wires from the bottom of the fuse box that you are talking about. Definitely afraid that I will create more fuse problems. I am not your average mercedes diy'er. I will have to leave that to the professionals. This is something that I can have someone else try though. Thank you for your response.

My first MB, a 300CD, had a similar problem. Spent hours tracing wires. I found the pin switch on the passenger side had grounded. It seemed to work OK visually. But it was trashed.

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Selling used Mercedes parts on Ebay...always changing...
cdplayer51 take a look!
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You have a short somewhere. Unfortunitly finding it is going to take some time. You need to a multi meter, and the wiring diagrams. Grab a beer and start testing and tracing.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200

If, when you disconnected the antenna in the trunk, you left the 6 or 9 pin wire connection that is on the driver's side beneath the false wall loose, it will absolutely cause the fuse to blow when the pin ground against the sheet metal of the car. Don't ask me how I know. Reconnect this, or wrap it with an insulating material, and see if the problem persists. You never know, you could get lucky.

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Tjohn

82 300 SD
77 450 SL (gone)

You have no other choice but to start at the beginning. Doc. is the only one who hit it on the head,As you say if you are not comfortable with doing the wire's,Then find an indy that will start at that point,If you don't it will not be an easy or cheep job.Some mec's love this type of job,they get to rack up lot's of hours.But to find the short you will need to rig up a tester with a fuse,Make each end with alligator clip's,one end to the battery,the other to the wire,When you find the bad wire the fuse will blow. Have fun JNT

Is the pin switch on the driver's side or the passenger side. (CD Player) said he found a problem with the pin switch on the passenger side whereas (tjohn) said check the pin switch on the side of the antenna. This is the driver's side. I just checked the wires on the antenna side and everything looks ok. By the way, is the 6 or 9 pin switch referring to a switch with 6 or 9 prongs. Thanks to all of you for your help. I will be calling my indy. if I can't fix the problem in the next week or so.

Took car to my electrician at work and we took the false wall off in the power antenna area and low and behold the first thing that we saw was a chafed wire tied around the bottom of the power antenna mounting bracket. I was floored. I had checked the power antenna connections but I did not remove the false wall. The chafed wire was at the bottom and you couldn't see it unless you removed this wall. It only took 10 minutes. Problem solved. When I had the radio installed at Circuit City, they really did a shobby job. They left wires in position to get trapped. I wanna personally thank M.B. Doc, Tjohn, just-n-time. You guys really steered me in the right direction. I was just about to go to my indy. and let him try and find the problem. My I was without these lights for some months now and now I'm back in business. You are the greatest. Thank you, thank you.

Congrats! This is a great place for help. Now go enjoy your car again

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Tjohn

82 300 SD
77 450 SL (gone)

Tjohn. You're absolutely right. I am enjoying it again. It's nice to see at night when you open the doors again. Thank you. (By the way where in va. do you live) are you in the tidewater area.