Car Alarms: Security Alarm, chevrolet express, conversion van

Question
My Dad who is 80 years old is trying to sell his 2003 Chevrolet Express 1500 Regency conversion van however his alarm has been going off, this began infrequently but now it is going off more frequently. This all started when he moved the van at his home from 1 location and then to the driveway.  It has been sitting for some time. The only way he knows how to keep it from going off is to disconnect the battery.  He tells me Regency most likely installed the alarm and that it is not factory installed.  he has taken it to an alarm company, they charged him 50.00 to look at it but they cannot figure it out, needless to say he still had to pay the 50 bucks.  He lives in Dallas, Texas and I live in Charlotte, NC, I am been trying to help him with this issue long distance but am having no luck.  Any suggestions would be most appreciated, he is at his wits end.  Thank you.  Shelly Mathes

Answer
Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Ok let's clear up the terminology glitch here.

1. FACTORY/OEM alarm = Part of the original schematics
and plans from the manufacturer.
(horn honk, head lights flash, Starter may crank and
die, no spark)

2. DEALER INSTALLED alarm = Just that. Once the vehicle
is brought to a dealer, the dealer sub contracts the after market
security out.
(horn might honk, siren and parking lights flash, starter kill relay,
no start, no crank, just dead.)

3. AFTER MARKET alarm: Same as #2 but Customer IS AWARE that
the system was put in at the dealership, but may not
be informed of the brand name, or even what it's
total capabilities are.
(siren & parking lights flash, starter kill)

Which one applies to yours?

RM/ALARMTEK
CARALARMMAN.COM