Alarm issues on shore power

alta825 · 07-27-2014, 06:02 PM

Having an odd issue and I'm not sure where to even start looking. The Viper alarm that was installed on my van will go off by itself whenever the van is connected to shore power.

Any ideas?

Alarm works fine when it's not plugged in and per the voltmeter my house battery seems to be charging just fine...

Scalf77 · 07-27-2014, 08:29 PM

A guess would be that it your Separator closes and charges the Van Battery also. It could be that the alarm senses the voltage increase when the van is not running. I would try and disable the separator, that is if you have a separator.

-greg

JWA · 07-28-2014, 04:06 AM

Another issue affecting unwanted alarm soundings is an errant ground connection. When/if that's interrupted then reconnected the alarm might be triggered. If something in your charging or separator system causes that momentary loss of alarm ground it needs to be repaired or rewired.

86Scotty · 07-28-2014, 08:40 AM

I have an Autopage alarm and do NOT have this problem. I too think it's probably a ground issue. Did you install the alarm? Or do you know where the brain (control box) is? I would start tracing grounds. There are several alarm components that are grounded so you may need the installation manual.

alta825 · 07-28-2014, 07:25 PM

The alarm was installed by SMB or their steep guys back in 02 with the orig build. I've poked around a little and haven't located the brain. Where would I typically find the separator on a 50 type of build? Under the bench with all the wiring or under the hood?
Thx for the help

**BroncoHauler** · 07-28-2014, 07:39 PM

I know SMB Fresno has Integrated Audio out of Fresno do their AV installs. Whether they had them do it back in '02 I don't know.

Somewhere I have Rob's (owner of Integrated Audio) e-mail and phone number. I'll see if I can find it.

Herb

alta825 · 07-28-2014, 07:45 PM

Awesome Herb-thank you!

86Scotty · 07-28-2014, 07:50 PM

Id be willing to bet its in the passenger side kick panel. There or under dash on drivers side. It'll be a black plastic box. If you are fairly good with electronics you can get the model number off the brain, find the instructions via PDF on manufacturers website and go from there. But without a manual or experience I wouldn't mess with it.

**daveb** · 07-28-2014, 08:12 PM

Does the van have an inverter or converter?

Most early vans have an isolator. Those are generally on the firewall under the hood. They are prone to corrosion and that can be an issue if the shore charger is trying to charge the house battery. If it's going bad and passing current back to the engine system I can see it tripping the alarm.

If you had a separator installed by SMB I'd think you might have a starting battery going bad. In that case the battery box of the bad battery might feel warmer than the other(s) after a charge. Could even be a bad or loose battery connection.

After looking over the alarm connections I'd check all the batteries and connections and then look at the isolator. A poor ground can cause all sorts of bad stuff to happen.

AKSeeker · 10-24-2015, 07:16 AM

I'm having a similar problem with my otherwise very reliable Viper alarm on my SMB,.. Only what happens is that the alarm is triggered when I plug it into shore power at home. No problem if unplugged, or if disarm the alarm, then plug in and re-arm. I know what you're thinking,.. But the problem is that if we have one of our weekly brief power outages, when the power comes back on the alarm is triggered. If we're not at home, the alarm sounding is a neighborhood nuisance and "crying wolf" conditioning everyone to ignore it. The Viper alarm was professionally installed by a third party stereo system vendor about 3000 miles away from where I live.