Alarm Problems - E240 'X' Reg Est (2000) .../Continued!

[Wattoh]

Several of you very kindly made suggestions re my dodgy alarm (my initial thread 26 May 06). It is still playing up! Siren replaced then brake stop switch. No joy! Had 4 days no problem last week, then it started again.

Merc dealer said they would need the car for an hour and investigate - but what would the do in an hour? Just look at the computer? My local indep Merc garage has done that, but has suggested leaving the car with them for as long as poss, to monitor (and charge an hour's work).

What if the computer keeps throwing something else up? Change every electronic component one-by-one? Can the entire alarm system be re-set or replaced?

One thing I have noticed is that the Tow Protection switch pleases itself as to when it lights up: with alarm set or unset, when car is being driven or parked - sometimes it is lit up and sometimes not! On one occasion, it was flickering - not flashing (as if a loose connection).

Might this indicate a dodgy switch or dodgy sensors in the ceiling? Might be a good place for the next investigation to start, anyway!

Thanks!

 

[Blobcat]

If it only started after the water problem then I would still investigate that. You said in your previous post that the cabling was damp. I would get some water repellant contact cleaner and go through all the switches and contacts you can that got wet.

 

[Wattoh]

Thank you. I have peeled back a little of the interior that runs over the inside wheel arch and see that there are loads of cables where it got wet. Difficult to get into that area to spray them (reluctant to do so without seeing what's in there exactly!) - or even simply let them 'air' in the warm weather.

Could the fuses underneath the seat be affected? They did not get wet, but could general dampness affect them? I am reluctant to WD40 them (or the pump also under the seat).

Can I safely spray the contacts on the battery (if I do not disconnect the terminals first)?

 

[Blobcat]

The battery terminals unless really 'furred' up should be fine. As for the fueses pls don't use WD40 as it gums them up. If you suspect they have been wet pull them out and clean them up one by one (replacing each one before removing the next) whilst the fuse is out spray contact cleaner into the contacts. I would try and find any multi-way connectors as well and give them a good dose of contact cleaner. If you have a Maplins nearby they sell contact cleaner.

 

[PINBALL]

What-hoh, wattoh!

Firstly, thres no info in your profile about which model it is?

Does it have the original alarm fitted in factory, or has this been replaced with another aftermarket that includes fuel cut off?

So lets presume its original, firstly I would look for any bad earthing perhaps caused by water damage in the past, so try to see where alarm unit is earthed & see if its come loose etc.

If youve got a trailer warning lamp - Lucky You! (all I've got is cheapo buzzers that are useless when radio is on).
This is a good indication that somethings not right as it should only illuminate when the trailer plug is connected to show indicator bulbs on trailer are working properly.

If it were me having those probs I would take it to Road Radio or a tow-bar specialist - somone specialising in electrics & have the electrical loom joints for the towbar looked at asap - before something worse may, or could happen.

Where'd you get the car from a proper dealer, or other source?
How long have you had it?

Hope it helps,

Keith.

 

[Blobcat]

Hi Pinball - Heres the history http://forums.mercedesclub.org.uk/showthread.php?t=18458&highlight=alarm+problems

 

[PINBALL]

Many thanks Blobcat,
& Apologies to Wattoh!

If the cars now dried out?
Could the computer be re-set by dissconnecting the battery for a short while of say 10 mins or so, to see what goes amiss 1st?
Which could give some indication of what could be causing this anomally?

Also, before this forum was born many moons ago, I remember having had a problem sorted out by the local dealer FOC with a courtesy car for the day, due to thier being directed on what to look for from Milton Keynes head office technical help team - the number for which can be got from most uk produced Mercedes brochures - usually in small print on the back, just make sure you have your log book with you to give them the vin No. of your car.

Don't give up on it just yet!

Hope it helps,
Keith.

 

[Wattoh]

Thank you for your thoughts Blobcat and Pinball. The car does not have a towbar. The light I mentioned was the "tow protection/sensor on-off" switch on the dash).

I think my wife (with 3 kids in tow!) will be taking the car to the local indep garage tomorrow and they have said they will monitor it every morning to see if the alarm has gone off overnight.

Another thought: I think I have the original battery (year 2000, 115K miles). I think also that the alarm is not a problem for some days after long, high-speed journeys. The car is not used for driving to work and unless we go away for a weekend, only has short hops around west London - sometimes not moving for 7-10 days at a stretch, or a trip to Sainsburys. Could the battery be on its way out/be failing to hold its charge??? and could this upset the alarm?

Just a thought!

 

[PINBALL]

Good guess W

Funnily enough have just posted "what a difference a new battery makes" inder electrics forum on this site, and youv'e just reminded me why I wrote it in the main place !!!!!

Key pad button battery wasn't lasting very long before me having to replace it with a new battery every 12-20 weeks.
Since changing battery on car have noticed that remote key works better n from longer distances - but have yet to see if remote battery lasts any longer.

If you do go for another battery, perhaps after getting it tested like I did, make sure its equivilent amperage output or greater, don't be fooled into thinking a smaller / cheaper version will be just as good.

Good luck
Keith.

 

[Wattoh]

Thanks Pinball. I read your post before checking further replies to mine!

Who was the Battery Specialist you went to? Was it someone like Kwik-Fit? I would not know what the 'ideal' reading was to demonstrate that the battery was good, and I fear that they would throw some gobbledigook at me and tell me I needed a new battery - even if I didn't. [How cynical is that?] Anyhow, what sort of organisation should I be looking for? Could any trusted local garage help or does it need somebody more specialist? I live in west London.

Thank you!

 

[PINBALL]

Hi there W
Sorry for delay,

A local garage would normally be happy to test your battery, but I would book it into a Battery or Merc specialist independant (unknown to me, as I don't live there).

If you start a new thread on "Benz related" discussion furum, I'm sure someone will answer in that area pointing to reccomended garages etc.

OR look in ylw pages for a Varta / Bosch (german battery) specialist.
There are loads of inferior makes of battery inc Kwik fit & Halfords, but lets face it you only get what you pay for & if they were as good as they like to think they are, then how come the manufacturers like MB, BMW n Volvo don't fit them & reduce costs? - mostly cos they aint no good at standing up to the cars demand on amperage, or thier extended warranties from new.

Your driving the best, so fit the best for just a few quid more.
Good luck & keep us informed about resolving your original problem please.
Keith.

 

[Wattoh]

Thank you!

Since driving from London to Devon and back Friday/Sunday 16-18 June, I have left car alarmed and - touch wood - it has not gone off! Since when, it has only had one short hop to Kew and back (6 miles total).

Will monitor for a little while longer before investigating further.