MB

New to the list and looking forward to years of fun with our new 968. We just replaced my wife's S2 Cab (for sale) with her dream car, a 1995 968 Cab. We are having a problem with the alarms sounding at random times of the day without being touched. It will time out, but comes back on awhile later. The central door lock switch is also not working, which may be related. Also (and I'm not sure if this can be related but...) the interior light also does not come on when the door opens (there is power and it can be manually switched on). I need to start troubleshooting, but also need to bypass or shut off the alarms so that she can lock the car until I get it fixed. I have searched the archives on this and other sites and have had no luck finding the info I need.

1. How do you shut off the alarms on a 1995 968?
2. Any ideas about where to start the trouble shooting process? Will a disabled central lock (no light on console, no door relays clicking when switch toggled) set off the alarms after awhile?

Steve

MB

Helpful to note what I've tried:
The triggers on the doors, hood, trunk, and glove box are all working but I'm still getting the double flash. There is an aftermarket radio, so the missing stock radio can also be sending the signal to the alarm? Anyone know where that stigger is? Is is internal to the radio or a pressure switch that's just open somewhere? Any suggestions would be appreciated.
Steve

AllenM

I had a similar problem and it turned out to be wires chewed through by a rodent on the hood switch. They were frayed and would touch randomly, usually at 4:00am for some reason. I doubt that this is your problem, but here is how you can lock your car without setting the alarm. Actually, I just re-read your original post and saw that your door lock switch doesn't work.
If it WAS working, you can lock the car using the central switch with the passenger door open, then close the door, the alarm will not be armed, but the car is locked.

I would start w/ trouble shooting the interior lights and central switch. Also, check the glovebox again. You can adjust the latch point, and it may be at a point now where it is barely pushing in the switch. I think there is a phillips head screw or something that will make it latch farther back and push the door switch farther in. This is a common cause of weird alarm problems.

Good luck to you.

Randy_J

Check all the grounds under the instrument panel and especially the door pin switches - bad electrical grounds on these cars are notorious. Do a search for the main grounding points - it's an easy first round item to see if it helps. Also, some of these electrical connectors are getting on 20 years now and corrosion and losing good contact could be a cause for intermittent issues. I found that just disconnect and reconnecting goes a long way to resolving maladies. Just be methodical, patient and use a little common sense before doing the tough / expensive options. Good luck and congrats - post some photos of your new car.

MB

I think I've ruled out the easy stuff. Open each door, hold in the switch, double flashes, let go of the switch, alarm goes off. Same thing for the hood, trunk and glove box switches. Central locks and radio are still unknowns. Are the alarms tied to the lights? The trunk, glovebox, and hood lights are out. The interior light can be switched on manually, but does not come on with the door opening. Vuses all look good.

Does anyone know how to disable the alarms so my wife can lock this thing when she drives it? Does anyone know how/where the radio was tied into the alarm system?

Randy_J

Should not be.


are the bulbs OK? If they are, get a voltmeter in there and check for voltage. Sounds like grounds are bad, especially if you get 12V on the VOM


This sounds like pin switch problems or wiring that is shorting

Did you try cleaning off the ground points for the harnesses? Here's the diagram - it really is very quick to do, and may help. Worth the try as it will only take 30-45 minutes to cover most of these. The main ground strap - the one off the battery to the chassis and block is also pretty marginal. I replaced mine with ones that Iceshark used to make. I think Rennbay does those harnesses now.

The ones to really check are GP VI, GP X - the main negative ground strap points on the firewall behind the battery and at the rear of the engine block - both tough to access. And GP II under the dash to the left of the steerng column (lie on the DS footwell and look up for the bundle of brown ground wires - that is the main grounding point for all the instruments and panel eletricals) and GP VII (can't recall where that one is right now - it might be behind the instrument panel oval surround - that will be the radio ground).

Randy_J

hmm... further to my previous post, whenever I run into mysterious electrical issues with these cars (I have 3 - 944 NA, 951S, 968 Cab) I get a phillips screwdriver and actually unscrew those door pin switches and check for corrosion - they are exposed to a lot of water and a little sandpaper to clean them off before reinstalling them at least eliminates that contact point as a possible culprit. With all the intermittent issues you are facing, it might be worth going after the simple stuff a little deeper. I've had pin switches that seem to work when depressed manually, yet on closer inspection are badly corroded, etc. While you have access to the wiring, even moving it in/out a little from the rubber boots etc might help to eliminate a frayed wire, etc that is shorting out. Case in point - when I repaired the PS door handle on my 968, on reassembly, the remote lock trigger wire got looped around the wrong side of the window regulator so that lowering the window 3" resulted in a "short" - that triggered the alarm in a way that was extremely difficult to determine. I finally found it by wiggling the wires and noted that there was no play at all - hence the solution. Would never have found it otherwise. So wiggle the wiring looms, especially the ones going into the door for the locks and check the switches by unscrewing / sanding / reinstalling. It might work.

Good luck!