My Hymer B660 is fitted with the Waeco MS-650 alarm. No PIN was supplied with it, and the dealers are less than helpful. I don't want to brute force trying the PIN (only two digits!) because I don't know whether it will permanently lock out after n attempts. I'm not currently in a position to drive it all the way to the dealers for them to examine. On handover, I was shown how to use the Mercedes Keyfob to lock & alarm the van. I have been using that method up until a few days ago assuming all was OK when I stopped to think why the indicators flash three times on arming. Hours and hours on the internet trying to find a useful users manual have failed - I can only find an installation / commissioning manual. (I did find a more comprehensive manual for the later, MS660 model, but that's not much use, I don't think?) From what I can glean, three flashes seems to signify a problem but without the PIN, I can't interrogate the system. I have checked as many of the magnetic reeds as possible and the ones I can get to seem to provide appropriate voltages when open vs. closed. If I try and arm it with a door open, I still get the same three flashes. Arming it while still inside gives three flashes. Neither scenario causes the alarm to trigger. Finally, there is no alarm contact fitted to the bonnet. I assume this is because the starter battery is inside the main body? Does anyone have any knowledge of these alarms, where to get a manual, or who to go to for diagnosis / fix? Would like to have a resolution before we depart for Germany next week! BTW, I'm based halfway between Wigan and Warrington.