Alarm help please

[Eiknujrac]

Ok so this is the deal:

I own and drive a 1991 300e, and have for the past couple of months been trying to diagnose why the alarm in my car is not working at all. I have confirmed the presence of an alarm, from the white alarm horn on the drivers side behind the headlight, the hood switch, and the module under the passenger side footwell. But for the life of me I can't figure out why It won't work. Would the installation of an aftermarket head unit have anything to do with the non-working state of my alarm? From what I read the stock alarms were fairly well tied in with the stock radios.

Any ideas would be appreciated, i've checked most fuses and connections, but anything helps.

Thanks

-E

[sixto]

The alarm brain box is between a removable panel and the firewall in the passenger footwell. I expect you'll find that the box is disconnected. I expect it is so because the door lock switches for the alarm became flaky and caused the alarm to go off when not intended.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

[Eiknujrac]

Yea I checked the passenger footwell connections, and the black connections are all plugged in along with the red, none of them are disconnected.

[sixto]

Does it arm if you set it from the trunk? The trunk switch is the least likely to go bad.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

[Eiknujrac]

Just went out and tried that, but it didn't work.

Is there any way or a certain wire to check if the system is even getting power?