Doesn't make sense

[collon]

I have two problems and would be grateful for any bright ideas...three visits from RAC/Merc mechanic and a visit to a Merc specialist are puzzled. E Class 220dEstate. 2019. Al;arm going off randomly. Merc engineer disconnected OHP - diagnostics showed internal motion sensor at fault. Alarm went off twice withing half an hour. He returned to reconnect OHP and disconnect siren. Withing half an hour alarm triggered - flashing hazards. Third visit - diagnostics showed nothing particular and suggested lock with blade key,thus not setting alarm until i visit garage. Unfortunately locking the car with blade does not lock the estate boot. My insurer tells me car not insured if left unlocked. I had the previous model where there was a switch on boot door to lock it - but apparently this doesn't exist on the 2019 model which seems to me like a massive overlook. Any ideas please on 1) the alarm situation (diagnostics show no particular fault) and 2) perhaps most important - how do I secure my vehicle until it gets to its appointment? So far experts flummoxed - any better thoughts out there?

 

[Blobcat]

Hello and welcome,

I'd check for a corroded alarm siren and/or water damaged SAM module

 

[ajlsl600]

Hello and welcome,

I'd check for a corroded alarm siren and/or water damaged SAM module

If ti's batt in siren check that out.. another shxxe design bat dies leaks on pcb £100 gone. Plus hassle

 

[Wighty]

Sounds like it need a new OHP to resolve it either way ?