Electrical Fault
 

Hi, I have a 75 Saloon, 2.5 V6 petrol on a 53 plate about 68000 miles so far and last night the alarm started going off, I reset it and then today it did the same again, so thinking that the wind (which has been really really strong here) may be moving the car and causing it to go off I re-parked,

When I went to get in the seat was not in the right position (electric seat!) so I rest that as well, re parked and forgot about it.

Then the alarm went off again, I turned it off again using the remote and then noticed that the wipers were going off as well.

Went out to check and they were switched off, so reset and left it again.

Then about 10 minutes later the alarm went off again, with the wipers going as soon as I turned it off.

Then (!) it went off again but this time without the wipers.....so I can looking for a solution on line and found this forum....any ideas? (it seems to be OK again now, and didn't go off all day after sounding once this morning until about an hour ago!)

Thanks guys in advance if any of you have any ideas otherwise its off to the dealers at some point this week.

Morning Laurence,

Check that your 'plenum chamber' isn't flooded with rainwater. This is the area between the foot of the windscreen and the engine compartment bulkhead and is the home of the main ECU. Leaves find their way into it and block the drain holes. The chamber fills up and soaks the ECU resulting in inexplicable fault conditions such as the ones you describe. A search of the forum should bring up lots of information to help you.

Simon.

Not on a 75 but on one of my beemers I had similar electrical gremlins which were caused by the battery going down and causing volt drops/surges etc. to the various systems and upsetting the ecu's for seats and wipers and obviously an alarm will go off if it registers a large voltage drop or in the 75's case something moving in the cabin (seat?)

Might be, might not be your problem

Good luck..

i agree with the post re battery going down . when i first got my car the alarm was going over like yours 1 week later the car wouldnt turn over ,would jump start but turn on the key .new battey fitted and it never did it again .

Battery
 

After checking the plenum drain I found that a similar fault was caused by a corroded battery terminal. This came off battery in my hand when I pulled it. Bit of a miracle my car was moving at all!

Worth a check

Chris

Hi all. My tourer behaved in a similar fashion not long after i got her. Traced mine to a thimble full of water in the sat nav unit cradle. Water was getting in via the 2 nuts under the fuel cap that secere the sat nav cradle and trickling down the bracket into it. Silicone on said nuts and tightened up, sorted. If you car has sat nav might be worth a look.
Would never have found it without pointers from the good folk here. Now been fine for over 2 yrs !
Regards Mark