PrimaryNumbers

Hi Guys,

First time post. To say my issue is bizarre and hard to diagnose would be a bit of an understatement. Here's the deal.

My 2002 996 CS4 appears to have some type of short when the tempature rises outside. I live in Southern California so it can get kind of warm. So here is basically what happens.

Issue 1: My car can be sitting parked and will randomly just honk. Two quick honks.

Issue 2: I can be driving the doors will lock & unlock, the center dash light will flash and the car will honk (two quick honks). It is random how often it does this, sometimes 20 times in 10 min's sometimes once in an hour. There doesn't appear to be ANY pattern.

Issue 3: Which may or may not be related to issue 1 & 2 has to do with the automatic windows. Basically when you open the door the window comes down slightly.. this feature has become very sparatic.

I have removed the circuit breaker for the horn but that does not seem to have mattered at all.

All three issues appear to somehow be related to the heat as the car never randomly honks in the morning or the night.

Any ideas would be awesome.

Loren

Sounds like you have an alarm controller fault.
You will need to Durametric, a PST2, or PIWIS tester to fully diagnose the issue(s).

ZX9RCAM

My car did some crazy stuff when water got splashed inside, but stopped as soon as it dried out.

Ubermensch

Agreed. It sounds like there's an intermittent problem with one of the sensors/switches in the alarm system. It trips and the alarm system honks the horn to let you know it has a fault. From what you've said it sounds like you've probably narrowed it down to a window switch, but the test systems that Loren mentioned will confirm.

Dale Gribble

Control box under the seat is worth inspecting. I just had my alarm, central locking system and interior lights die (all on same circuit) because of some wires that were bare under there. If liquids or excess humidity were to creep in, that could be a source of issues. A local 996 cab just had that happen as well.