Yesterday it was in the upper 90's temperature. When driving down the freeway I needed the horn and when I pressed it did not work. I tried a number of to,es and no horn. When I got off the freeway I tried the horn again and did not work. A few minutes later I tried again and it worked.

We then parked the car for a few,hours and again the horn stopped working. I got home and parked the car and turned it off. 5 minutes later I went to start the car and the alarm went off, the car started but the horn was beeping and lights were flashing. Turned off the car and the alarm went off. Started var again and alarm went off. I then turned it off, locked the car with the key, unlocked and them started and this time no alarm. Checked the horn and it did not work.

Went to start the car this morning with no alarm issues, but horn once again worked and did not work.

This is a 2007 R350 with 66k miles that is still under starmark. Any thoughts on what this could be for when I take it in? Seems like an electrical issue, but to sure where the horn function and alarm come together.

Thanks

That sounds like the security module is failing.
It may also be a K40 and/or SAM module

I would start by having the battery and alternator tested...

Have it scanned by the DEALER for codes.

I suspect one of these..
Possible:
MB# 1645403072
MB# 1649004800
MB# 1645400672
MB# 1645402501
MB# 1645406501
There are many other possible causes.

roy@pelicanparts.com


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