Please help - I am moving and need to drive the car tonight, but the alarm or horn, hard to tell which, goes off when I put on the headlights on my 1990 300 SEL.

I disconnected the alarm (underneathe the passenger side 4 years ago so I doubt it's that). But do not know.

I had a mechanic replace a rotor about a week ago and the ABS stayed on after that and also the outside temperature light does not go on as well anymore. Been busy so I haven't taken it back yet.

I took out the fuses for the "warning system" and "horn", but when I turn the headlights on, a super loud sound comes out under the hood.

Heard of this? How can I disconnect? Please help, I need to drive the car tonight.

Matt
1990 300 SEL

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)

You need to disable the alarm horn. It's located in the windshield wiper motor area. Remove the weatherstripping, remove the retaining clips. Lift up the passenger side and the horn like apparatus is the thing you need to disable. You should be able to just reach in with it lifted up and unscrew(phillips head as i recall) the power going to it. You have the option of removing the wipers and lifting the whole thing off for greater access. I recall just lifting up the passenger edge and doing it. Fixing the fault, I have no idea. Mine will occasionally still flash the headlights after locking it. But the alarm does not sound, and the lights flashing ends after a minute I think.


'94 SL 500 40,000
'91 300SD 534,000
'87 300SDSL 236,000

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jcciem
'94 SL5000 60,000
'91 350SDL 545,000
'91 350SD 197,000
'00 E55 AMG 77,000

Thank you very much - I appreciate it.


By the way, what do you think is causing this? If I was to fix it - what would I do?

In the meantime, disconnecting the alarm hound sounds like the way to go.

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)

That's very bizarre. Disconnecting the alarm module under the passenger footwell should completely disable the alarm. There are two wire groups that go to the alarm, and they should both be disconnected.

The relays that flash the lights and honk the horn are inside that unit, so there is no way you can get the alarm to go off with it disconnected unless you have some after market alarm system installed.



-tp

Very true, it is bizarre. I disconnected the alarm around 4 years ago. When the alarm goes off, I hear a clicking noise, but it goes away in a few minutes.


But when I turn on the headlights, I hear a very loud noise, and it is not as loud as the horn (steering wheel).


Could replacing a rotor for the brakes have anything to do with this? I had one put on a month ago and the "ABS" light is still on and never took it back to get it fixed.

Thanks!

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)

Does anyone have a picture of what the alarm horn looks like?

could disabling somehow screw up the headlamps?

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)