So I unlock my drivers door and then, without opening the drivers door went to open my trunk and the alarm goes off. Hmmmmm.

I called the Benz mechanic, they said just lock the car. That did not work. After 2 cycles of the alarm going off, it stops. Ok, great.

The car is unlocked, I decide, I'll open the front door and then put my car cover in the trunk. But noooooo. The alarm goes of again when I open the drivers door. Again, 2 cycles and it stops.

The cycles are alarm noise, followed by blinking lights and then alarm noise again.

It seems that if I open the passenger door, the alarm does not go off.

What am I doing wrong? If anything. Can someone explain it to me? Appreciate the help.

I've seen great detail in how to disable the alarm but would prefer to keep it if I can. Almost sounds like a common problem on w201, 1988 2.3

Likely the switch in the driver's door handle tumbler that deactivates the alarm is faulty. To shut down the beeping one can unlock the passenger side door. To fix you replace the door lock tumbler. It is an expensive part and a "patch" is to swap the right and left sides but that requires a re-wire of the switches since they arm and disarm in opposite directions.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

That makes a lot of sense. Thanks