Put new battery in VW Golf and now it won't start. Help!
December 13, 2011 7:09 AM   Subscribe

Battery died in a Volkswagen Golf. New battery connected and now whenever the car door is opened the alarm goes off, which came as a shock because we didn't know the car had an alarm! Disconnecting a thin blue wire on the negative battery terminal disables the alarm but the car won't start -- dash lights come on, radio plays fine, but the engine doesn't even make a sound. Just dead. Presumably an immobiliser. Help!

The car is used and we have no manuals or documentation. It looks like its an original key, however.
posted by humblepigeon to Travel & Transportation around United Kingdom (14 answers total) 1 user marked this as a favorite
Some cars store information that let's it know that a battery was disconnected; it appears the VW Golf is one of them.

It seems you have two options: 1) Have it towed to a dealer to have the alarm reset, or 2) follow the instructions in the link above to disable the alarm system.
posted by TinWhistle at 7:19 AM on December 13, 2011 [1 favorite]

What year is the Golf? This is very important when diagnosing these beasts.

As an example...MkIV Golfs have a poorly-made door-lock module in the driver's door that is highly prone to failing. Symptoms range from the doors locking themselves while unattended, up to the car becoming immobilized and the alarm going off.
posted by Thorzdad at 7:30 AM on December 13, 2011 [1 favorite]

Also...That thin blue wire on the negative terminal sounds suspiciously like an aftermarket alarm connection. Did you buy this car used?
posted by Thorzdad at 7:31 AM on December 13, 2011

Response by poster: It's a 95/96 model.

Yes, the car was bought used. It's almost certainly an aftermarket alarm system because there are two strange sensors in the car mounted near the window. But it seems the problem is the immobilizer, regardless of whether the alarm is connected or not. In both cases the engine won't start and appears to be dead.
posted by humblepigeon at 7:34 AM on December 13, 2011

The VWs with factory alarms from the mid 90s to present that've had to deal with in the US, Mexico and Germany will make an audible horn chirp when you lock the door either with the remote fob or regular key in the lock. Obviously, if you had a the key fob you'd be aware of having an alarm. My 1996 VW didn't have a remote fob, but it did have an alarm that would chirp when I locked the doors. My newer cars had the fob. I rented a VW Golf in Mexico of that vintage than it was really stripped down compared to mine but it to had a factory alarm.

I've had to replace the battery only my Americanized VWs with the stock alarms and the process did not disrupt normal operation of the alarm.

What I'm thinking is your used VW has may have an aftermarket alarm that was "reawakened" after you replaced the battery. I've only see the battery terminals on my 96 and 08 VWs and that Mexican rental (long story). I don't recall any extra wires connecting to the battery. Because you don't have the alarm's FOB, it sets off the alarm and removing that wire disables the engine just like you'd want if you if your car was actually being stolen.

Golfs have been sold around the world for decades. Your profile indicates you live in the UK. However, it might be useful if you also included the year and country to help in troubleshooting.
posted by birdherder at 7:34 AM on December 13, 2011

Response by poster: It's a 95/96 model and there's just one key with it. No fob. Although there are sensors inside, there's been no indication of an alarm in all the years it's been used. No chirp when the doors are locked.

Other strange things worth mentioning: there's a single LED light near the controls on the dash that used to flash but is now on constantly (almost certainly part of the alarm system).

By attaching the battery when we were already in the car, we noticed the alarm wouldn't sound. However, the hazard warning lights flashed periodically -- three seconds on, three seconds not on. Then the alarm went off again once a few cycles of this had passed.

So basically we have to find out how to reset an after market alarm system, the make and model number we don't know about?
posted by humblepigeon at 7:42 AM on December 13, 2011

Best answer: I'm afraid you're likely going to have to haul the car to a qualified alarm installer and have the aftermarket alarm deactivated and removed. The immobilizer has been tripped and, without the matching fob, there probably isn't anything you can do.

Is there an odd-looking button attached somewhere in the interior? Something similar to this?
posted by Thorzdad at 7:49 AM on December 13, 2011

Best answer: (shows me I should preview)

Since it sounds like it is an aftermarket alarm, I think you'll need to figure out how to disable/remove it to get your car running properly again. To do that you'll need to know the brand (and vintage, if the original owner installed in the mid nineties it could be a huge pain to find the documentation) and I have no idea how to do that except to follow that wire from the battery and hope for the best. You may need to find a mechanic versed in aftermarket alarms to help you (shops that install new alarm systems may know). I'd probably want to make sure that old alarm is completely excised from your car or it may reawaken again and leave you stranded. Or perhaps independent garages that specialize in VWs may be another. Taking it to a VW dealer may fix it, but they'll probably charge you more than you paid for the car to fix it.

Good luck. I loved my 96 VW Jetta and even though I'm driving a high end 08 now, I'll sometime miss that old green machine.
posted by birdherder at 7:50 AM on December 13, 2011 [1 favorite]

Response by poster: No button anywhere. We looked for anything at all looked programmable or pressable.
posted by humblepigeon at 8:00 AM on December 13, 2011

I second the advice of Thorzdad.
Find a shop that sells and installs aftermarket alarm systems. They'll know what to look for as far the equipment and wiring go and thus be able to remove it properly.
posted by nickthetourist at 8:42 AM on December 13, 2011

Have you followed that blue wire to see where it ends? I would think it goes to some sort of box that might have google-able info printed on it. Note that the blue wire might pass into the main cabin of the car, in which case you'd be looking for that box under a seat or under the dash.
posted by stephennelson at 9:10 AM on December 13, 2011

The problem, of course, is that the aftermarket immobilizer is spliced-into the ignition harness. Removing it from the system without knowing exactly what you're doing could result in worse problems. Electronics in VWs, even models that old, are tricky, delicate, and easily hurt.
posted by Thorzdad at 9:20 AM on December 13, 2011

Best answer: This may sound crazy, but my girlfriend's VW Beetle's alarm kept going off after I messed with the battery and the solution was to open the hatchback with the key. Somehow this reset it. Weird, but worth a try maybe?
posted by orme at 10:14 AM on December 13, 2011

I had a non-VW car (a Ford Festiva, to be exact - probably a 95 or 96) that suddenly sprouted an alarm one day after battery problems. I had *no idea* the alarm was there.

I actually went through the little fuse box and found one that the alarm was connected to. I pulled out the fuse and the alarm shut up. It didn't seem to affect anything else in the car, so I just left the fuse out the rest of the time I owned the car.
posted by tacodave at 2:45 PM on December 13, 2011 [1 favorite]

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