Hello All,

My daughter who is away at college in VA just called me to say that with the key out of the ignition, the horning is honking spontaneously, and the headlights are going on and off spontaneously. The honking of the horn and the flashing lights are occuring separately and not in tandem. Also she said the turn signal are coming on and off without touching the turn signal. I told her to immediately bring the car to a local garage. Does anybody have any idea what is causing all these problems?

I was thinking maybe a worn ignition switch? Or maybe the electrical harness is shorting out. The car is 26 years old and has 365,000 miles on it. It is a 1996 850 GLT Wagon, non-turbo with a 5-speed manual.

Any advice or suggestions are deeply appreciated.

Hugh

Hello All,

I want to share with all who helped me with their advice and comments what was the cause of the problem I described above. The Anti-Theft Alarm Relay, Part # 9128903 was failing. It looks like a big relay fuse or module and it has a double plug. It is large, about 2 1/2 long and 1 inch wide, with a red color plastic cap. I think it plugs under the dashboard. My garage which specializes, diagnosed the problem. Volvo doesn't sell this relay anymore, but fortunately the garage had some used relays they saved off old parts cars. I was very lucky they had one.

I am relieved. I thought the problem may have been due to short in the wiring harness due to age or possibly a short in the ignition system. I've had the car back for a few days and no problems. I want you to all know, when I dropped off the car, I printed all your suggestions and provided them to the garage. You collective advice may well have lead to the diagnosis. "You've done good!"

Hugh

Squirrel nesting?
Chipmunk storage device under the hood?

Not the ignition key.
--
Keeping it running is better than buying new

Klaus and all who responded. The problem appears to have been caused by a drop cloth being caught in the rear door latch, preventing it from closing properly. I keep a drop cloth in the rear portion of the car. My daughter failed to keep it clear of where the the striker hits the latch. However, the mechanic also chased a mouse out of the car. How long he was a resident or where he spent his time is unknown. The car seems to work properly now. Thank you all for responding.

Hugh

The evil resident might caused some problems in the wiring, do a close inspection when you have some time.

Honda sells a specific tape for protecting the wire hardness with it.

hi hugh,

do you have an after market alarm?
have your daughter confirm that the headlights are flashing, it should
be only the front and rear turn signal lights and the side indicator lights.

the following is for the stock 1995 850 volvo alarm- a complex circuit that does not cycle the headlights. hopefully the 96 is the same.

first you can unplug the alarm horn 16/19, its mounted in the engine bay on the center of the firewall up high. there's a 2 pole connector.

there are 6 alarm switches that are involved that must close;
one at each door lock
one at the tailgate lock
one at the drivers side hood latch

this mean if there's a door ajar it can cause trouble, have your daughter open and close all the doors, tailgate and hood.

check that all of the locks function ok with central locking? have her check that all the door locks cycle up and down, and that the tailgate also locks. if you have a dead lock motor somewhere it could upset the alarm.

the hood switch can be checked with an ohm meter at the hood latch assembly.
make sure it's plugged in.

i'd do this stuff before looking at the alarm relay 2/28 or the central lock relay 2/7

i'd want to service the many ground points involved with the alarm system:
31/50 31/11 31/47 31/48 31/50 31/51 -they all need to be healthy.

you can disable cental locking and the horn with fuse 6
disable the flashing lights with fuse 13, not sure if will kill directionals?

ref 5-door alarm pg 114 of the volvo 1995 850 wiring diagram tp3907202
component & ground locations pg 116
you must find your volvo wiring diagram to diagnose wiring issues.

start with above and post back

good luck, bill

ps: sorry for ugly typing w no caps, i'm typing one handed after triceps tendon surgury

Howdy Bill,

Saw your note about typing and triceps tendon surgery. How did that go? I can totally relate! Just went through wrist reconstruction surgery 2 months ago. It was my right and dominate hand/arm. Felt like I was handicapped. Still do a little...:) Was the surgery on your dominant arm?

Jim
--
Will I buy another Volvo??? We'll see....

hi jim,

sorry about your wrist.
i'm right handed and my left arm is in a brace.
i start lengthy rehab tomorrow.

i hoped to find your email in your profile since this is not a volvo subject.
check my profile and please email me to discuss the successful triceps tendon surgery and comprehensive cashechtomy from the ortho group i have.

bill

B.B.

Thank you for this "exhaustive" road map of how to approach this problem. "Exhaustive" is a compliment to you. I will try to email your answer to my daughter, or mail it to her. She brought the 1996 850 GLT Wagon to a local garage, but it will not get to it until Thursday of this week. They are backed up with work.

The alarm system on this 1996 850 is the factory installed alarm. It is not an aftermarket unit.

B.B. again thank you for taking the time to provide this detailed analysis of how to diagnose this problem. Your answer demonstrates the value of "brickboard.com".

Hugh

If the issue is a malfunctioning alarm system, then the car will likely not start.

Been a long while since I owned an 850, but I recall accidentally setting off the alarm (reaching through the window to unlock the door). It was a not so easy task to silence it. IIRC the key wouldn't work in the ignition and neither did the keyless entry clicker. Only cycling the key in the door lock finally did it.

First things first is to disconnect the wires to the horns; no good decisions can happen with that noise.

If will start then I'd look into the wiring at the steering wheel/column. The turn signals, hi-beam switch, and horn is all right there.

There are little red plastic retainers on the horn contacts in the steering wheel that are prone to embrittlement and turning to dust with age, usually causing the horn to simply stay on. No reason for that to affect the headlights though.

Good luck,
Will
--
XC60 / Odyssey

Will,

Thank you for your reply. I don't think it is the alarm system. My daughter is able to start up drive the car. Also, the horn spontaneous beeps as she is driving along. Also, the headlights turn on by themselves. I have a suspicion the problem is due to wiring that has dried out and cracked due to age. When the problem is diagnosed, I will post it.

Hugh

Hi,

I don’t know too much about these 850 cars. I’m. 240 man only!
I can barely recognize the differences with so many brands out there.

Does this car have an alarm system? Sure sounds like it’s operating!

Is it possible that the hand remote button has a stuck panic button?
Might be a low battery inside remote and no longer has the strength to disarm the car too?
Electrics can be deceiving over simple things.

Try disconnecting the car battery and maybe that will reset the alarm system to zero.

Just a few simple ideas that young drivers haven’t experienced.

Phil

Phil,

Thank you for your response. My daughter does not have a remote key fob with her. She just has an ordinary key to start the car. As I mentioned, the car horn goes off. I don't think it is the horn that is dedicated to the alarm system. The 84=50 has two conventional horns in the front of the engine bay, just in front of the radiator, if I recall correctly. Then there is a single horn attached dead center to the firewalk. I heard the horn briefly as I spoke to my daughter and it did not sound like the horn dedicated to the alarm, but to the car horn triggered by pressing down on the central hub of the steering wheel. Also, when the alarm is triggered on the car, all you hear is the alarm horn and the headlights do not flash. I suspect the problem may be related to the ignition switch or the wiring harness. Something is shorting out on this car, even without the key in the ignition. I will post an answer when the problem is finally diagnosed.

Hugh

Bet it is the alarm going off! All 850's came with a factory alarm system. With the age of your car maybe there is a shorted wire somewhere? Disconnect the battery. Then check the wiring. My 95 850's alarm went off unexpectedly once. Unfortunately, I don't recall how I shut it off. My car didn't have a key fob. I'm guessing maybe yours doesn't either?

Checking the condition of the battery cables might be a diagnostic starting place. Not sure if this will directly affect the alarm system though. Have her look for corrosion and deteriorated wiring on the positive cable specifically. My 95's positive cable was nearing replacement before I sold the car. Sooner or later all battery cables need to be replaced.
--
Will I buy another Volvo??? We'll see....

Jwalker,

Thank you for your reply. My 1996 850 does have a key fob, but my daughter is only using a regular key to start and turn off the car. The key fob that came with the car is designed only to open and close the doors.

I do keep an eye on the battery cables. Every so often I clean them with water and baking soda, air dry them with an air hose, and then cover them with white grease to prevent corrosion from forming. Typically this regimen seems to work. I will advise my daughter to check the terminals. Fortunately she was able to drive it to a local garage that has a very good reputation. When I learn of the diagnosis, I will post it.

Hugh