Golf IV - alarm going off for no reason,doors locking by themselves ....

Did you experience an electrical interruption recently? Some alarm systems will set to 'default mode' under those conditions, such that even the slightest vibration will trigger the alarm. Once when my wife' Saab had such a problem, whenever a heavy freight train went by (every morning, 3:00am) on the tracks about 1/2 mile away, the alarm would trip. There is a way to set the sensitivity via the door key...

But from the other symptoms you describe, it sound more like you have a bad ground somewhere that is causing the problem. Or road salts have gotten into some circuitry or sensors and causing false trips. It may well all be related including the rear wiper.

I do not know where the CPU is for the alarm, on our former Mercedes, the present Saab and Volvo, it is beneath a plate on the passenger front seat. It is very well protected in these cars, no clue as to how well VW protects it.

Peter Wieck Wyncote, PA

thanks!

no electrical interruption recently, just out of a sudden.

well it has been damp in the past few days and they have been throwing loads of salt on the roads, so could be something of the sort.

I have checked around the car in search of the alarm CPU, but no luck. well, if it starts honking again in approx 30 min time I'll just disconnect the battery for the night and go to a garage tomorrow, as it's really starting to annoy me.

I just hope it doesn't cost me tons of money (as do most of my VW repairs!!! unfortunately)

martha

Sounds like a bad door lock assembly. The lock assembly contains microswitches that sense when the door is locked, when it's unlocked, when it's open, and when it's closed. The microswitches are known to fail and will exhibit exactly the behavior you describe. Replacing the lock assembly runs in the $250.00 (US) range.

I was going to say rear hatch latch or the wires to the hatch might be breaking and shorting out.

I had a similar problem. The rear washer hose comes undone and messes with the alarm. Take a look at

That could explain the alarm going off when set, but would not explain the doors locking by themselves.

Hi, thank you all for your suggestions, I definitely think you have a point. A bit of an update. I got fed up yesterday evening, went out and unplugged the battery (so everyone slept well). This morning took the car to a garage, we tried it, waited, checked a bit, and nothing whatsoever happened... this car is becoming a real mystery. The car has been parked in front of the house for 6 hours and the alarm hasn't gone off (yet). Btw - the rear windscreen wiper is attempting to function now - somewhat slowly though, so the garage guy thinks it might be the motor. (I'll have a look around scrapyards for a spare). I also think that the alarm and the doors locking are two separate problems (possibly somehow connected), i.e. the doors locking thing started first, so this weekend I'll dismantle the driver's door and have a look at the wires and all. I think there is definitely a problem with the driver's door, as I have had the window up/down thing changed twice (you know that bit that aaaaaalways breaks on golf iv

- the little bit of plastic - and you get stuck with a window half open on a rainy day) and since the last one the locking system hasn't been the same. Baz - thanks for that website - definitely will be doing that this weekend!! Will keep you posted! thank you

Martha

hold on - I was reading through the rear screen washer repair instructions, and it says - "An alternative symptom of a failed rear screen washer can be a break in the feed tube inside the wiper motor assembly, which allows the washer jet to rotate with the wiper arm " - my washer jet always squirts a bit to the left, never straight and it moves with the wiper arm - it's been doing so for ages, basically since when I bought it - so it shouldn't be doing that? It should always be squirting straight, right? Umpf, I have an exciting weekend in front of me.... hope it doesn't rain!

ok how do the power locks unlock the rear hatch latch? It should unlock when you unlock all of the doors and it should remotely unlock/unlatch when you press it's button. Is the hatch latch lock electric and/or operated with air. I am not sure but I was thinking if the wires were breaking and shorting to one another then power or ground could make it's way to the power door lock module. I have seen broken wires between the doors and their pillars create problems with the locks and windows. Not sure if they caused the alarm to sound, but it is possible.

Just trying to think of ONE common area where all the problems could be! ;-)

later, dave (One out of many daves)

Baz you were right!!!! Just a quick note to say that I have just stripped the rear panel and everything is wet, going to B&Q do get some stuf and repair the thing!! thank you all!!!

martha