VR Calais factory alarm starts for no reason - advice please

[Holden4fun]

Hi guys,
94 VR Calais (stock). Alarm sounding when car parked and locked after an hour or so. Also blowing fuse for interior lights occasionally. Pulled fuse for interior & boot lights - alarm still sounds when car left for a while in sun. I pulled bonnet switch (corroded) out of circuit - alarm still goes off. Pulled horn - alarm still sounds through anti theft horn. Pulled all horns - no sound but I think lights flash so alarm activated. Can I cut the alarm system out? Is there a fuse to disable the lot? Auto elec said it may take all day to find!! Appreciate any advice. Thankyou

[The1]

is all the interior door locks going down?

[Holden4fun]

The1, Yes all the central locking is working ok. and when the alarm sounds I use the remote to open the doors and stop the alarm.

[The1]

ok you may have to get someone with a scantool to hookup and see if there is error codes in the bcm perhaps. You could also try resetting the BCM it's on the fuel pump fuse in the engine bay, pull the fuse for a few seconds to reset the BCM.

[Holden4fun]

The1
Thanks for the replies. I will look see if I can get codes checked. Auto elec said process of elimination. Would just try things and wait to see if it tripped again but not sure where to start. This is a good way to burn up $ with no guaranteed positive outcome. These (and all more modern) cars are great until the gremlins get into the electronics - you just can't see the little buggers to isolate them!!
Thanks again

[aceventura]

I had exactly this problem when I bought my VS second-hand. The car alarm would go off in the middle of the night, and the interior light would blow quite often. It turned out that the dealers were aware of the problem before I bought the car and had also reasoned that the car alarm and interior light problems were related. I think they didn't fix it in the hope that the dealer warranty would expire before I discovered the problem. Lucky for me the problem presented while it was still under the 3 month warranty. I would hate to think how much it would have cost to fix otherwise, cause it took them about 5 hours to find the problem.

The problem was traced back to a wire in the interior lighting circuit that had the insulation rubbed off it. I cannot remember whether this wire was also associated with the alarm system, or whether there was an adjacent wire from the alarm system that also had the insulation rubbed off it. The auto electrician told me that the wire (or wires?) had become worn in the region along the drivers side rear window pillar. Has been 9 years without an issue, so they definitely fixed the problem.

Hope your problem is as simple as this.

[Holden4fun]

Thankyou for the info. Had the hood lining fixed the other day and looked at all the interior wires. Looked ok but I have an issue with the passenger rear light. I have turned both the back lights to not operate with the door. Waiting to see if this means no alarm trip.
Thankyou