factory alarm system
 

Have a 2004 RX8 and have run into one problem with the alarm system. Every time it rains the alarm goes off. Both the horn and flashers or just flasher. Has anybody else have this problem.

Well......that's a new one. I haven't heard of that before.
Did an advanced search yield anything?
Couple quick questions:

You have water in either tail light?
You have a spoiler on the car? If so.......which one?
Is the inside of the trunk dry?

don't have water in tail lights. haven't found anything on advance. regular spoiler on trunk and tunk is dry.

I have a 2004 with the same problem. It just started this year! Seems to be after it rains, or today... after a car wash! I had a problem with one of the tail lights taking on water a few years ago but have sealed them and they've been dry for a couple years.

I will subscribe to this thread and update if I figure it out!

Crossing my fingers!
 

So i had the same problem where after it rained the alarm would randomly go off with the car parked in my driveway or at work.

I replaced both of the door sensors -- these appear to be the only moving parts in the alarm system (at least for a 2004) -- no trunk or hood sensor.

After replacing about 6 weeks ago, it has been fine.

Part number for the switches is DD1066540A. They are about $11 each. Took about 5 minutes to replace each (assuming you have the correct size star-head screwdriver).