Viano alarm & electrics

[murf62]

I have a w639 2008 Viano and battery/alternator visit workshop warning comes on just after starting. The alternator is charging (14.3V) and the battery is good.

Other symptoms which may or may not be related:

Indicators flash about 2x faster than they should, hazard lights flash normally.

Intermittently the horn will stay on (alarm?) until I disconnect the battery to stop it.

It has a towbar fitted, maybe it's related to that? I am assuming water has got somewhere it shouldn't have during the heavy rains recently.

Any ideas anyone?

 

[m80]

Intermittently the horn will stay on (alarm?) until I disconnect the battery to stop it.

Is it the horn or the alarm siren that sounds?

It is possible that your SAM has seen moisture / water, It isn't uncommon.

 

[murf62]

Is it the horn or the alarm siren that sounds?

It is possible that your SAM has seen moisture / water, It isn't uncommon.

It sounds like the horn. Does the alarm siren sound different? I can't remember.

Water in the SAM is pretty likely I guess, is it under bonnet in the fuse box? Went through some heavy rain and floods over the weekend.

 

[m80]

Assuming the alarm is functioning you can lock with the fob and then open a door with the blade key. That should trigger the alarm.
Alternatively lock with fob while sat inside, then wave your arms.
You'll then know the difference in the sounds.

SAM is in the under bonnet fuse enclosure, along with TCU and ECU. It is held underside of the fuse tray by a torx screw from above.
A good 2nd hand, identical, SAM off ebay is plug and play.

 

[murf62]

Thanks. I'll pull it out tomorrow and see if drying it out helps before buying one.

 

[m80]

see if drying it out helps

It doesn't in my experience. But good luck.

 

[murf62]

So,moisture must have gotten into it (or it's associated connections/fuses) when I had to open the fusebox cover in torrential rain to sort a headlamp problem. I took the cover off the fusebox and ran the engine for an hour or so with bonnet closed to dry it out. All faults now cleared down. Fingers crossed, it's sorted.