My 996.2 has had its share of problems lately. Since December I have had an unresolved intermittent misfire on cylinder 1 (replacing that plug, coil, and fuel injector did not solve the problem).
Starting this week, the front trunk (aka frunk) started popping open every time I unlock the car. This happens with two different key fobs, so I know it's the car and not the key. That's not so bad, because I can just push the trunk shut. What is bad is that the trunk started popping open every time drive. Fortunately there is the manual backup latch, so I can still see where I'm going.
Has anyone else seen or solved this problem?

 

Any other weird gremlins? When weird things happen I default to ignition switch.

 

Yes, more gremlins:

The same day this started, after driving home from work, the radiator cooling fans were on full blast on a cool evening with the coolant temperature gauge right at 180 F (the normal operating temperature). Normally on my car, the coolant temperature must be a lot hotter for the fans to turn on. The engine compartment fan was also on.

The next morning when I hooked up my Durametric, the coolant, oil, and ambient temperatures all read about the same temperature (about 55 F), so they seem OK, at least when cold. I forgot to check the engine compartment sensor.

 

Yesterday I pulled out the fuse for the DME for a minute, then replaced it. This didn't seem to change anything.

 

Hm... Can you check the trunk release switch near the door sill and make sure there isn't any signs of water in there? Also, it's controlled by the alarm control module under the driver seat. Make sure there is no water or damage to any of the wiring in there. If you want to trace the wiring up to the actuator I believe it comes up the left side of the front trunk. You have to remove that plastic trim piece around the brake fluid res and the front trunk carpet. Also, of course, check for faults and you can check to see if the alarm module is getting a command to open the trunk or if it's doing it on its own. You can check this by looking at "actual values/input signals" in the alarm control module via the scan tool. If it's doing it on its own it's probably a wiring issue or the actuator. If it's getting the command it probably has something to do with the wiring at the module actuator or switch by the door switch.

edit: Just saw your new information. Check the front cowl area for standing water. If there is any signs of water make sure you clean the cowl drains very well as those can allow water into weird places.

 

Thanks. I'll check those. It's been raining hard here in northern California, so wet electronics is a suspect.

 

Ya, I know you guys have been getting hit hard so that's why I'm thinking it may be water related. Let us know what you find.

 

I was thinking the same thing about wet electronics making crazy sh*t happen. I hope that's not the case...everything dry in the cabin?

 

I have seen zero water leaking into the cabin or the trunk. I just get some window fogging when it's cold. When it's humid, I run the air conditioner to dry the air blowing into the cabin. Fortunately I park out of the rain at work and at home.

 

Dry in the cabin is important to be sure but the doors want to be dry too.

The door membrane - or window seal -- can leak and let water in the door.

From this water then initially the door lock or window acts up but if the problem is not addressed soon the electrical problems start to show up at other seemingly unrelated areas.

While just recently I checked and found both door bottoms wet on my Boxster there were no electrical gremlins. The tech resealed one membrane and replaced the other and the door bottoms are dry once again.

To the OP then check the cabin for signs of moisture, the body water drains for signs of blockage, but also check the door bottoms for any dampness. If you feel some give the door a shake and listen for water sloshing. Regardless if you hear water or not the door needs to be opened up and the reason for the water in the door addressed. Reseal the membrane or replace it or even replace teh window seals. However, I these latter seem to be pretty durable. The tech had orders to replace them if he felt they needed to be replaced but he said they were fine. The water was getting past leaking/torn membrane.

 

Another reason the 99' is the best 996.

 

+1 for checking the front cowl drain to the right and left of the battery. Those drain plugs can easily get clogged and moisture can run down the firewall.

If it fills up it can also destroy your brake booster.

 

Thanks guys for all of the suggestions. The inside of the firewall was completely dry with no sign of water. Under the brake booster was also dry. The drains to the left and right of the battery had a little crud in them, but I saw no sign that they were plugged up and caused water to fill up that volume.
Inside the cabin, I looked near the button for the trunk and it felt totally dry.

Based on Macster's suggestion, I looked closely at the door. There is a bundle of wires inside of a rubber tube that goes from the body to the body to the door. At the door, the tube was loose, which could allow water to get in. I removed the inside panel, which was a royal PITA. Below is what it looked like after carefully peeling and cutting back the foam sound insulation.



The plastic volume attached to the rear of the speaker is huge. I had to peel back the sound insulation even more to remove this speaker assembly.



Note how large the plastic cavity is compared to the little speaker and my shoe.

Under the speaker assembly, the bottom of the door was completely dry, but it was dirty, so some water and grime may have entered in the past.

At this point I reconnected the battery, which was disconnected to prevent shorting something or setting off the airbag. I tested locking the door with the remote...and it worked fine--no opening the trunk.
I reassembled the door, periodically reconnecting the battery and using the remote. It still worked correctly. I road tested the car, and the trunk still didn't pop open.

I don't know what happened to fix the problem, but it seems to be fixed now!

 

My frunk did the same just after I bought it. It turned out to be muck near the switch on the door sill. Bad location really.

 

Had the same problem a few years ago. It was a bit of grit under the switch that would move around under acceleration and trip the switch. Solution: compressed air and vacuum cleaner to really clean the area and the problem never reappeared. Try that before you start replacing parts.