Minor 987 electrical bugaboos...

Hey gang, Having some minor electrical gremlins with my 2010 987.2 Boxster Base . Curious as to what you guys think. 1) The rear trunk light doesn’t automatically turn on when you open the trunk. Meanwhile, the connection to the trunk light is functional; I can use my PIWIS to test the connection and turn it on/off. This leads me to think it’s a failed or dirty microswitch at the rear trunk latch – as I can still electronically release the trunk switch to open the trunk. I figure the next step is to go into the latch and try to clean the microswitches; my guess is that some microswitch is telling the car that it is always in the closed position and hence won't turn on the light. (In my next drive this week, I'll leave the trunk unlatched and will see if it throws a "trunk open" error.) Meanwhile, how does one easily remove that black plastic that surrounds the trunk latch? 2) Albeit not quite the same situation, it is somewhat similar as to what's going on with the passenger door. When the windows are up, there's no issue and everything seems to behave normally (including the windows being slightly down until the door is shut). But with the windows down, I think the car thinks that the passenger door is always closed. In this instance, in contrast to the driver's door, the cabin (interior) lights don't turn on when you open the door. Plus, when alarmed, when opening the passenger door from the inside, it won't set off the alarm. Could someone with a 987 (ideally 987.2 ) please verify if this is incorrect behavior for the passenger door? In all cases, the door locks/unlocks fine electronically. (Also, in my next drive this week, I'll leave the door slightly ajar and will see if it throws a "passenger door open" error.) 3) Finally, I'm wondering if someone had disconnected the horn from the alarm system. When the alarm is set off, only the lights flash on/off on the car -- which is kind of useless. Plus, the car does not make any horn chirping sound when locking or unlocking the car. Any experience out there for checking the horn and alarm connections? (Maybe someone was annoyed by the alarm going off or a locking "chirp" and disconnected a wire?) Thanks, everyone!

For #2, I just checked my car. The interior lights do turn on when I open the passenger door (windows closed). For #3, I can tell you that arming/disarming does not honk the horn. I wish it did (as do many others), but it cannot be done on this car even with PIWIS or other programming. You only get light flashes (2 flashes when it locks, after a small initial delay... and 1 flash immediately at unlock). I haven't set off my alarm, so I don't know what happens then, but I'd imagine the horn must honk at that time? Does your horn work at all (ie, via the steering wheel)?

Thanks, @schwinn ! 1) To clarify, the interior lights do indeed turn on here when the passenger door is shut, and the windows are closed. I guess my question is if this is still the case when the windows are down. Also, if the windows are down, car is locked, and the alarm is set, will opening the passenger door from the inside set off the alarm? That doesn't seem to be happening here, but does happen for the driver's door. Thanks for confirming about the "beep" thing; yup - I get the flashes. The horn does work (steering wheel) - so I am guessing it may be a horn disconnection at the alarm box (wherever that may be).

I tinkered for a bit in my car to see what happens. Here's what I found: 1) With both windows open or closed, opening either door does turn on the interior lights, as expected. 2) If the doors are locked, you wait about 10 seconds for the system to fully arm (I believe that's what's happening while the central-locking button flashes fast during this time). Once flashing goes slow, if I open either door (I opened from inside since the doors were locked and windows were open)... the "alarm" does go off. But, in my case as well, there is no noise - just flashing lights. Weird. I waited an extra 10-15 seconds thinking that maybe it would delay putting on a noise, but it never did... 3) Not related directly to your questions, but note that there is a "Passenger Compartment" monitor component of the alarm. This apparently monitors for movement inside the passenger cabin when the alarm is on. I found this to be very insensitive - I could wave around throughout the compartment with no effect. I did manage to get it to trip when I waved around near the back of the center console... but even this wasn't consistent. The manual says something about not having the seats "too far back" to prevent this monitoring... but I'm 6' so I can't imagine moving seats just for this to work? 4) I also have read in the manual and online that if any of the alarm points are not latched, the horn will honk to indicate this. The glovebox is one latch point, so if that switch fails or if the glovebox is open, that can sometimes cause this to happen. I tested this on my car and, the horn does NOT honk to indicate a problem. The alarm does appear to notice the open glovebox, because the central-locking LED stays solid for the first 10 seconds (versus flashing fast)... so it's seeing it, but again it's not making any noise/horn. So, maybe my car is suffering from the same no-horn problem as yours. In addition, I tripped the alarm by opening the door from this state, and it was tripped (lights flashed) - so the good news is that the remaining latch points are still monitored, but the horn never makes noise. In my case, horn works for the steering as well, of course. I think we both have non-noisy alarms for some reason - no horn from the alarm system. In your case, I think there may be an additional issue - your passenger door should still turn on the interior lights and trip the alarm even if the window is open... assuming my car is a reference of what's correct behavior. I am going to call in @deilenberger on this matter, as he seems to know a lot about these cars and may be able to offer some insight (and/or he can call in other experts as well). Almost sounds like a horn relay isn't being hit from the alarm system only, or maybe there's a configuration issue in the car causing the horn to never fire with the alarm? I certainly would like it to do so!

Just FYI for you 2 fellas troubleshooting..... My 987.1 Boxster does include the horn honking if the alarm is triggered. But I do NOT get a horn signal when I remote lock the car. I only get the lights for confirmation. I need to go to the barn and test if I hit the lock button a second time does it beep the horn? That would be similar to what my trucks do when I lock them remotely. (2012 & 2021 F150)

Thanks so much, you two. @snakebitten -- Thanks for confirming that my horn connection to the alarm is either disconnected or there's a failing relay. I do remember the first time hearing the horn trying to go off...but it was like it didn't have enough juice. Again, it makes me wonder if there's a failing relay as honking the horn works fine. @schwinn -- * Sounds like there's something not right with my passenger door. BTW - This was tested with the top down and the windows down. I'll have to re-check. * I noticed the 10 second or so delay for the system to arm, so that appears to work. * See above per the horn not going off... sounds like we're in the same boat here. Only the lights flash. * I never got the "passenger compartment" monitor to work in this car, or in my 987.1. I too am 6' and that's kinda weird per the seats (they're always far back). I will check the glovebox as well. You guys rock. Thanks for chiming in.

Correct, the horn never noises when you lock the doors. Many have searched for a way to make this happen, but it doesn't seem possible. Just a note of warning, there is a setting in the Foxwell NT530 that lets you set "siren" in the rear module, however if you do this it still doesn't honk and it "breaks" the system so that the NT530 can't change it back - you need PIWIS at that point to restore it. Note that nothing hardware-wise breaks, but it doesn't work... so beware. (Frankly,. I'd be ok with adding a chirp module to the car if that's all it needs, but that's a different discussion.) From what I've read, the horn will honk if there is a fault in the alarm latching devices. So, if you leave the glovebox open, that should cause a honk when you arm the system. Some people looking for the honk have done this as a way to generate a honk on locking. I was afraid that this meant the alarm wouldn't arm, but it seems that's not the case, so this might be an option I want to exercise as well... if I can get the honk to work. As for pressing lock again... maybe 987.1 cars have separate lock/unlock buttons, in which case give that a shot. 987.2 has a single lock/unlock button, so pressing it a second time will unlock the car (and still not honk). @snakebitten - Does your car honk if the glovebox is left open and the car is armed? Also, when you trip your alarm (ie, open the door while armed) will your horn make nose with the flashing lights (hazard lights, basically - headlights stay off, of course).

You are right that I only have one button for lock/unlock on the Porsche , so I guess a double lock isn't possible. And I don't know if it will honk with the glove box open when I lock it, but I will verify and report. I have set off my alarm a few times when I let the car sit a few days and it went into hibernation mode. As soon as I open the door the horn starts honking and the lights flash continuously. I have to close the door and use the physical key to lock and then unlock the door to shut the alarm off. I don't have this happen if the car isn't hibernating, nor do I know how long it takes (in days) to go into deep sleep. I just know that it is because it will ignore the key Fob buttons.

Agreed. Note that some items do disable when the top is down. For example, I saw in the manual that if the top is down that the passenger compartment monitor is disabled too. so, there could be some codings like that, but I'd still expect the lights to turn on. For confirmation, my tests were all done with the top up. FWIW, I had to wave my hand or push my elbow into the area between the seats, just over the center console, and up to to the firewall. Again, it wasn't consistent, but that's the area where it seems to go off, if ever. It would be nice to know where, exactly, this sensor is... for reference. I recall having an old aftermarket alarm system on one of my previous cars (I worked at Radio Shack back then, so I got it from there, but it was likely a Viper rebrand). That system had an optional sensor for monitoring movement. I believe it would do so based on ultrasonic reflections as things moved inside. I never saw such a system elsewhere, but I wonder if that's what we have here, just from the factory. Again, would be nice to know what it is, where it is, and how it works... Honestly, I'd prefer if it was enabled when the top was down (that's what my old one was intended for) because that's when you want to detect people reaching into your car to steal something in the first place! Thanks... that's what we're all here for! Welcome to the party!

Awesome... do let us know! Funny, because my manual says that I need to press the unlock button to silence and disarm the alarm. I know that works because the flashing stops... I haven't tried the key-disarm yet, but I expect that might work too...

Great replies, guys. Many thanks for your help. I think I've figured out that there's a separate and very basic (like, my old vintage VW horn basic!) horn that is immediately to the right of the battery (driver's side of the car) that is completely SEPARATE from the car horn. From what I understand, it is used for locking/unlocking alerts and the alarm. So my guess is given that it sounds like it tried to honk but didn't when I set off the alarm, either there's a bad connection/ground somewhere -- or the horn is dying/dead. I'll have to go test the voltage and the horn itself during a free moment. Will keep you posted.

AHA! Excellent find. I didn't think that they'd use a separate horn for it, but that's what they did. So, I went to my car and found this: There's the horn to the right of the battery, under the metal tube. We're seeing it from the side here, with the blue arrow pointing to it. Here's another angle: And if you look carefully, you can see that my connector is disconnected from the horn... WTF. Thankfully, reconnecting this made the horn work again - I tested it by leaving the glovebox open and then locking the doors... and sure enough it beeped. As you noted, it's a pretty old-fashioned beep (you said like an old VW, which I'm not familiar with, but I'd almost say like an old-timey car). Maybe it sounds that way because it's been out of use for so long, but now it works. I'd try the alarm noise, but my wife is working from home so I don't want to alarm her (haha, pun intended). Anyway, looks like that's fixed for me now, thanks for the tip! I wonder why they left it disconnected... maybe the battery died and so the alarm kept going off or something, so this was the easy fix? I guess I'll find out if it keeps honking away in the future! Now I can disable the glovebox switch so that the alarm honks every time I lock the doors, too! Also, it might be interesting to replace that horn with something more modern sounding... should be easy enough to do since it's separate? Or maybe this is the second-tone of the normal horn as well, so it may need to "match" to make for a decent horn sound? Again, these things I cannot test at the moment... maybe later/tomorrow. EDIT: For info on the glovebox switch, check out this post: Where is the micro switch for the glove box?? The rest of the thread has a good discussion on the matter as well. I agree, maybe doing this isn't ideal, as it will beep whenever the trunk/frunk/door is open as well, and you wouldn't know it from the noise. The RemoteKey device seems to be a good alternative, especially since it offers other features (eg, the passenger-mirror-dip is nice, particularly since I can't enable it on my car via PIWIS/NT530 anyway, due to not having the necessary modules). Plus, this gets you a chirp instead of the horn noise when locking the car... much more modern sounding!

Dynamite, @schwinn -- Happy to help. Yup - it's an el-cheapo horn that's in there for the alarm system. I literally looks like a Bosch that was on my '68 VW Bug 'vert. Not surprised that someone disconnected it - it probably bothered a previous owner. Thrilled you got this sorted. More experimentation as the temps were high enough to go for a drive. I set the alarm with my sitting in the car and top/windows up (I didn't let it fully arm per the internal sensors -- I couldn't wait for that to set up). First, the passenger door did NOT set off the alarm when I opened it from the inside. So, I'm guessing it's a microswitch in the handle. Would love to confirm this before any repairs - it is a PITA apparently beyond belief. However, what did set it off was opening the glove box. Well, again it sounded like the horn barely tried to honk...and then quieted out (likely due to the car's dropping voltage as all the lights were flashing). So, I think my next step is pretty simple -- connect +12V to the horn itself and see if it works. I also could check the voltmeter of those leads (probably fine) and ensure it outputs +12V once the alarm goes off. Stay tuned and thanks again for your help, guys.

Wow - you guys have been intensely at this.. good stuff. Some stuff: It was designed not to beep/make-noise on locking. It only makes noise on locking if something it monitors isn't right. Dumb design IMHO, and I haven't heard of anyone who has solved that issue. Two clicks of the button will lock and then unlock it. There is no secret locking mode that enables the horn on locking. Glad you found the alarm horn, I'm actually surprised a bit that you guys didn't know it was there.. how could you miss it when dusting under the plastic in the Frunk? It is a simple Bosch horn - VW, BMW bikes, lots of vehicles used this one. They all use that same connector - so they're pretty much interchangeable if one goes bad. Good to hear it was just unplugged. The road-horns are behind the bumper - in a location that requires R&R of the bumper to replace them (BTDT). Sort of a PITA place to put them. If one were to disable the glovebox switch - you'd also lose your glovebox light, which could be a PITA when getting pulled over at night and having to dig around in the glovebox for your registration. Not that this would be an issue for you.. probably. Mine did honk when locking when my glovebox wasn't fully latching. Unfortunately, that also meant the light was on in the glovebox all the time. A bit of lube solved that issue. OK - so now a "does yours do this?" question on my part. When I get into my car and put the key in the ignition, and turn it to start - the right side window makes a noise like it's trying to go up, which it can't do since it's already up. Lasts perhaps 1/4 second or so. I can't think of any failure mode that would make it do this, so I'm thinking this might actually have been designed to do this. Does yours do this?

Haha - Thanks. I'm no engineer, but feel good when I figure stuff out. If things were designed a certain way, I like them working a certain way. Hence my love of German vehicles. I have "SmartTop" for my 981 . I love it, and it allows for some changes in the car. However, it seems pretty pointless with our 987s as we have to manually latch the top down anyhow. Don - It's super rare that you ask for testing! Happy to help. Checked this AM in my 987.2 and I do not get that passenger door window thing. Tested a few times. This was with windows up and top up. Engine was not started, but key was turned to I think both accessory and run positions. (Then again, given my passenger door issues, that may be part of the problem. However, it will lower/raise the window as it should.)

I went out to the car just now to do some testing of the window thing, and unfortunately I'm not seeing that behavior at all. I tried a few different things, including opening the passenger door (it drops 1/4" and raises as expected)... but it never re-raised when I started the car. I tried with the window up, partly down, door opened, door not-opened, etc... so I guess that means my car doesn't do that behavior? I'll be more aware of it going forward and keep an eye/ear out for it, but I guess that's not something I have happening? I could have sworn I heard some window movement in the past, like you described.

I'm not sure what triggers it on mine. It might be putting the key in the ignition. Cycling the ignition without removing the key didn't cause it to happen. I'll have to try to narrow down exactly what sequence causes this.. more to come.

@DS3 - Very accurate description of the sound. I keep trying to remember when I hear it - and I think it's when the key goes into the ignition, or the key goes to the on position. I'll have to check. Again.

Fyi, regarding the interior motion sensor.... On my 987.2 Boxster , the interior motion alarm sensor is located inside the center console, near the handbrake. It is part number 997-618-210-01. By default, the interior motion sensor is disabled when the roof is open. If you want to bypass this, and enable the interior motion sensor even when the convertible top is open, all you need to do is install the red clip up above the interior rearview mirror, so that the car thinks that the roof latch is engaged. This way you can have the interior motion alarm enabled when you park/lock/arm the car with the roof down. The red clips costs approximately $8, and is part number 986 -504- 986 -00. (Ex: Porsche Boxster Red Alarm Clip 986-504-986-00 ) I sometimes use this clip on my 987.2, so that if somebody reaches into the center area of the passenger cabin, they will set off the alarm. But beware, sunlight/shadows may interfere with the sensor, so you might get false alarms. That is why it is disabled by default.

Very interesting, thanks @Joe1406 ... some great info in that post! I never heard of the alarm clip, so that's news. Also, looking up the part number for the sensor, it's an IR sensor, hence the sensitivity to sunglight (which is loaded with IR). Seems weird that they'd choose an IR sensor. As I mentioned, I had an ultrasonic in the past, which worked great and wasn't sensitive to sunlight changes. Of course, an ultrasonic has to be "exposed" so that it can "see"... so it doesn't provide for as clean an installation, possibly... but it could have been figured out! Thanks again for the info... excellent detail!

For many years, I used to have the red clip for my 987.1 -- and I never seemed to be able to set off the alarm. Maybe I never waited long enough for it to arm (I guess it takes a while to map out), so it just sat in my dash unused. YMMV.