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Discussion Starter · #1 ·
Ok, I have looked through my Haynes manual and was a little dissapointed to realize that it didn't cover really simple things like wiring diagrams and locations for the horn. I am one horn away from getting my 85 300TD road worthy...any quick explanations on how to find the problem if the horn won't make a sound?

thanks
 

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1977 W123.123 1995 W124.034
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the horn on my 77 240d is behind the bumper on the drivers side and i had a similar problem with mine and i just rigged a second horn to a switch inside the car to pass inspection until i can fix mine... i suspect the contacts in the steering wheel have failed
 

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1984 300CD
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Are you saying that one horn is working and one Not? They are located behind the front bumper on either side. They have two different tones. You can purchase new ones, best price @ http://autohausaz.com (a sponser here)
 

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'78 240D
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in my Haynes manual there are probably 50 pages of wiring diagrams, in the back. hmm... i also think the contacts behind your wheel are bad or it'd be pretty obvious but you could definitely go to autozone and rig something up to pass inspection until you can order one from the link MBZ300CD posted. here in new orleans, when i have my car inspected they actually ask, "you wanna good one or a bad one?" anyway, if you cant find that wiring diagram anywhere (check the tech links at the top of the page) i'll scan it and e-mail it to you. just e-mail me at [email protected] or PM me.
 

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83 300 d t
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what state are you in cali doesnt have inspection thank god .i use to live in ct and remember fixing my floor boards in 82 dodge withe stop sign to pass . i made sure i put the stop facing in. you can put another generic horn under hood they wont know the difference . plus i dont recomend this way but it works usally you can fin a corupt insection place pay them 50 to 100 dollars and they dont even look at your car.
 

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Discussion Starter · #7 ·
The picture is great! Thanks also for the other input. I want to test the horn before I go digging through the wiring diagrams and contacts in the steering wheel...now that I can find it I can (I have been told) use a 12 volt battery to test the horn out. If that fails then I have a larger task ahead. Like learning to rig a horn.
 

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Discussion Starter · #8 ·
Ok, so after locating the fuse box, I determined that all fuses are accounted for and functioning. I took the horns off and connected them to a 12 volt battery to test them but then I realized I don't know what a good horn or a bad horn will sound like.

Both horns are able to pass an electric current thru them, they make a slight sound when I complete the circuit, but in no way would I describe it as a "horn" sound. Does anyone know of a better way to test a horn or if this way is ok what a healthy horn is supposed to sound like? I am dying to get my car on the road but it is killing me to be held up by something this little.
 

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'82 380 SL, '82 300TD, '85 500SEC
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Skogs...Just a couple suggestions how to proceed:

First.........Relax!!!!!

1. If in your battery to horn testing you connected the 12V+ battery terminal to the horn connection where the black/yellow/pink wire was...and you connected the negative battery terminal to the point where the brown wire was you would definititely know by having your ears ring that the horn was a good horn. It would be as loud as your ears could stand it at that distance.
2. If you made these connections properly and the horn did about nothing, it is dead. Through it away.
3. If there is a chance you mixed up the conections, do your testing over.
4. To expedite the situation, go to your nearest auto parts dealer and buy one inexpensive aftermarket horn.
5. Also buy a 12v tester or multi meter.
5a. Test the wires you left behind when you removed the horns. Use the test probes and connect one probe to the black/yellow/pink wire and the other probe to the brown wire. Have someone turn on the ignition switch and then press the horn button. If the wires are in good working order your tester should indicate 12v at the two wires when the horn button is activated.
6. If the wires are good, wire up and install the aftermarket horn as the instructions show and use the original horn wires. Then go drive the car and honk your brains out.
7. If you feel you have to "re-wire" everything, it's fairly straightforward but takes a longer time to type out than do.
8. Write back describing your results of steps 1-6 first.
 

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Discussion Starter · #10 ·
Excellent.

I'll get right on it and give it a try tomorrow. Thanks.

Skogs

daveward said:
Skogs...Just a couple suggestions how to proceed:

First.........Relax!!!!!

1. If in your battery to horn testing you connected the 12V+ battery terminal to the horn connection where the black/yellow/pink wire was...and you connected the negative battery terminal to the point where the brown wire was you would definititely know by having your ears ring that the horn was a good horn. It would be as loud as your ears could stand it at that distance.
2. If you made these connections properly and the horn did about nothing, it is dead. Through it away.
3. If there is a chance you mixed up the conections, do your testing over.
4. To expedite the situation, go to your nearest auto parts dealer and buy one inexpensive aftermarket horn.
5. Also buy a 12v tester or multi meter.
5a. Test the wires you left behind when you removed the horns. Use the test probes and connect one probe to the black/yellow/pink wire and the other probe to the brown wire. Have someone turn on the ignition switch and then press the horn button. If the wires are in good working order your tester should indicate 12v at the two wires when the horn button is activated.
6. If the wires are good, wire up and install the aftermarket horn as the instructions show and use the original horn wires. Then go drive the car and honk your brains out.
7. If you feel you have to "re-wire" everything, it's fairly straightforward but takes a longer time to type out than do.
8. Write back describing your results of steps 1-6 first.
 
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