Got this from my son. All my cars are older so I have no really good ideas of what to try, other than replacing the battery.

"So a few times over the past few months, I've gotten an error message on the message center when I went to get in the car saying "alarm activated", and my passenger door will randomly unlock itself. As a note ahead of time, I always use the alarm via door lock anytime I leave the car. Last Wednesday, I went to the car and tried to start it and got a series of clicks, like I was sparking but the engine was not turning over. I called in a friend to give a jump because I thought the battery had gone down and sure enough it started right up, drove home just fine, turned off the car and tried to start it again, no problem ,started right up. This morning the car started up just fine and I drove to work, parked the car and when I came out on break, again a series of clicks instead of starting. I called my wife, she came and we jumped the car. I let the car run for the rest of my break to feed some juice back into the battery , turned it off and started it right back up. I turn it off and close the door and noticed my interior lights did not go off when I locked the door I unlocked it, sat down, closed the door and the lights dimmed. I got out closed the door locked it and the lights dimmed. I went back out after work, and again I get a series of clicks no turn over. I had to leave it and come back. When I arrived I noticed that the interior lights were back on again. The battery was running on empty but I got in the car and closed the door and turned the key and noticed my message center said the passenger door was open. I went through and triple checked all the doors, all closed tight, nothing in the doorjamb, the message disappeared from the message center. Now it is giving me a reduced guard message. Anyways, Help! do I have an Alarm issue, battery issue, maybe a starter issue?"

I wonder if the random unlocking and message may be related to a switch in the door failing. I read a few posts lately somewhere talking about random locking / unlocking that was traced to a bad door switch and/or chafing wires at same.

But given the other symptoms, I'd also suspect the battery. How old is it? More than 4 years, and it's probably worth changing anyway.

You know, if Ben was driving the infamous Yellow Peril, he wouldn't have these issues!
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"Differences of opinions should be tolerated, but not if they're too different' - Sharon Craig

Ha ha ha! If the poor Yellow Peril was a little more reliable, he wouldn't be driving this car. It was getting to the point where Ben would have to work on it every night so he could drive it to work the next day.

The random unlocking was the actually the first symptom, a couple if months now. Maybe the switch/wire has gotten bad enough to cause a slow drain on the battery and gone downhill until we have reached the problems we have now.

I will pass all this and the tip from Dick about the plug on. Hopefully it will all be resolved by the end of the weekend. Thanks so much for your help!

Susan

On my 2012 S60 the plug in from the harness to the door harness was loose. May plug and unplug to see if that works.

dick

The 'clicking' noise when the starter is engaged is from the starter not having enough voltage to run the starter. Your starter is just fine, the battery is low.

A door open message means that the door switch was not closed completely, which could be a faulty switch ($$$). That will drain the battery. Slamming the passenger door is a good idea.

Depending on the age of the battery and the alternator, you may want to get a new battery. Any autoparts store can check the voltage output and battery. At idle, the alternator should be generating 14.3V or close to it. The battery should store about 12.5V, fully charged.
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My back feels better when I sit in a Volvo seat

I sent your response on to Ben. I was leaning towards the battery too, but the Reduced Guard thing and the passenger door signalling ajar and unlocking itself was throwing me off. Incidentally, he had to cut the bolts off the battery retainer. They just wouldn't budge. He ended up shredding the heads trying to get them off. So glad my dad saved every spare bolt, screw, washer and nut he came across for the last 60 years or so!