Install Woes on 1991 M5, Help?

Ok Guys, working on a '91 M5 at the shop today, Customer complained of Viper 300ESP alarm being intermittent, and wanted a new alarm installed, we couldn't duplicate the problem, but went ahead with the install of a python 1600. Install complete, no problems, 2 hours later, customer picked it up and complained that there was the same problem, sure enough, I tested it for about 20 minutes. And this is what I find, I arm the system, everything works fine, I disarm, workds fine, Arm again, works fine EXCEPT that the locks 1 second after locking, pop back up. Now this seems like a interface problem, but the REALLY weird thing is that it does it EXACTELY every other time, so it works for one arm/disarm cycle, then doesn't the next, no matter how much time is between cycles, I mean it is dead on, every other time. Any thoughts or ideas would be Very much appreciated. Rob,

is it possible the ign has to be cycled or something between arm and disarms cycles?Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

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Classic Car Audio

since 1979