Electrical Fault - I think

[Kingyd]

Hi,

I'm new to this forum so please go easy on me!!!

I have a B200 and recently i have noticed two strange things.

1. The Car alarm goes off randomly whilst sat on the drive way at home.
2. The red handbrake light and blue high beam dashboard lights flash intermittently whilst driving.

The car is 2012 B200 Automatic 'Blue Efficiency'.

A Diagnostic check indicated a faulty battery hence we have changed that but that does not appear to have fixed the issue.

As anybody seen anything like this before or have a clue what might be going on.

Thanks in advance.....

 

[richard]

When the alarm goes off, do the hazard's flash ? If not, the alarm is losing its "connection" to the car. This is often battery voltage dropping. Not heard of the other issue, but that does sound a bit like a voltage issue. Did you buy a decent battery, and have you had the alternator checked. 3-4 year old battery shouldn't have failed really.

R

 

[Kingyd]

Thanks for that Richard, Its the wife's car and i have never witnessed the alarm going off personally but we will keep an eye out for the hazards next time.

We did fit a decent battery and for now it appears OK. The car is booked in on March 7th for a diagnostic check.... lets see how it goes.

DK

 

[markjay]

If the faults have the same cause, them like Richard said usually several odd electrical faults point to earth connection issues.

Also as Richard pointed out, the alternator need to be checked as well, because when driving the current is provided by the alternator, not the car battery, so a weak battery should not in itself cause issues while driving (unless is is causing a short circuit).

If the two faults are unrelated, then the issue with the alarm could be failed rechargeable NiCd batteries inside the alaram sounder, in which case the sounder will need to be replaced (unless you are good with soldering on PCB).

Of course the alarm issue can also be due to faulty alarm sensor (i.e. internal volume sensors, doors or bonnet, tilt, etc etc).

 

[Kingyd]

Thanks for the replies.

The fault occurred again this week and i can confirm the hazards do flash when alarm goes off. Is there a way to determine which sensor is triggering the alarm i.e. boot, door, internal?

I will now look into replacing the alarm siren and or checking the earth/ground connections.

Thanks for the help.
DK