Locking problems - fluorescent light interference?

[brownne]

I`ve mentioned this before (problems with the second stage locking on my 2005 UK spec Prius) but I`ve got a new theory:

The locking problem happens a lot at night when I have put the car in my garage - the garage is lit with two low energy light bulbs (i.e. mini fluorescent) and there are two on the outside walls of the garage - It is possible that there is some interference from these bulbs which is confusing my key fob (note: no SMARTKEY in UK yet, just a remote operated key fob) ?

My dealer said it could be interference from electric garage door (don`t have one) or from radio transmitter (none near). The bulbs seem to be the only source of HF interference possible.

Has anyone else had a problem??

Thanks

[richard schumacher]

As someone who's worked on electromagnetic interference problems (though not on very similar hardware), I'd say it's possible. It's easy to test, no? Replace the fluorescents with incandescents experimentally, to see whether the problem goes away.

Presumably the fob is in your hand and somewhere near the car when you're trying to lock it? It's not inside a pocket or purse next to coins, keys, or a cellphone?

[tumbleweed]

Originally posted by brownne@Nov 8 2005, 02:13 PM
The bulbs seem to be the only source of HF interference possible.

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You didn't really mean HF (as in high frequency) did you? I assume you have tried all the simple stuff such as replacing the fob battery and trying the other fob. Also what did you mean by "second stage locking" it's not a term I'm familiar with? Does the car lock OK with the black buttons? Also try it from the other side, I think there are different antennas in each front door and maybe one in the hatchback as well.

Anyway it is an interesting problem, I too doubt it's the lights but I've been surprised before.

[Frank Hudon]

it's possible that the 50 HZ over there could set up a harmonic frequency that interferes with the fob. Also any cell phone towers near by?

[KMO]

Are you talking about the deadlock function on the second press of the lock button?

If so, yes that doesn't activate sometimes. It appears to be to do with the sequence the doors were opened then closed before the lock. I assume it's trying to avoid the situation of someone being locked inside, but I haven't figured out exactly which door sequences prohibit the deadlocks.

If it does fail to deadlock, unlock the car, open and shut the driver door, then deadlock again.

[USAnians - the deadlock function is possibly UK-only, and may relate to our lack of smart entry. When you press the lock button on the fob twice in succession, the interior door lock switches are disabled, so the doors cannot be opened by someone smashing the window and using the switch].

Otherwise, the manual does talk about the possibility of RF interference messing with the fob operation, but that would affect all lock/unlock transmissions equally, I would have thought.

[brownne]

Originally posted by KMO@Nov 8 2005, 11:10 PM
Are you talking about the deadlock function on the second press of the lock button?

If so, yes that doesn't activate sometimes. It appears to be to do with the sequence the doors were opened then closed before the lock. I assume it's trying to avoid the situation of someone being locked inside, but I haven't figured out exactly which door sequences prohibit the deadlocks.

If it does fail to deadlock, unlock the car, open and shut the driver door, then deadlock again.

[USAnians - the deadlock function is possibly UK-only, and may relate to our lack of smart entry. When you press the lock button on the fob twice in succession, the interior door lock switches are disabled, so the doors cannot be opened by someone smashing the window and using the switch].

Otherwise, the manual does talk about the possibility of RF interference messing with the fob operation, but that would affect all lock/unlock transmissions equally, I would have thought.

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Thanks to all for the advice.

I do mean the deadlock (it`s a useful feature so I don`t know why you don`t have it in the US??).
I`m glad someone else has seen this problem - I thought the problem might be related to the pin switch in the door (because, as you say, only by opening and closing the driver door does the problem go away - I`ve tried the other doors but no success) so my dealer changed it (though they don`t believe me even though it happened once at the dealership - they are in denial). The problem seemed to go away for a few weeks but then it started again (it doesn`t happen all the time and the two weeks might have just part of the natural distribution of occurence).

The opening pulse might be a different frequency (there must be something different about it) and might be less affected by whatever`s doing it?? My alarm has gone off a few times when I`ve pressed the open button though (not recently).

Then I thought it might be that I wasn`t shutting the door hard enough (even though the door open light is off), so I started slamming it shut. No better.

I thought about the door sequence but I can`t see a pattern, or any logic in it - I going to give this further investigation though since it`s a good point - my sequence of door opening and closing the doors when I put the car away is relatively consistent.

I called it HF (which is radio frequency in my book) since I kind of guessed that the starter circuitry in the bulb must be generating some RF noise (I know they generate harmonics) as well as some 50Hz noise. I might be wrong about the frequency though. There are no mobile phone transmitters nearby and I turn my phone off anyway when I leave work.

Changing the outdoor bulbs to filament is a bit tricky since they are in small bulkheads and filament bulbs are too bulbous. But I need to rule this out so tonight, when I put the car away, I turned all the lights off. It locked okay.

I`m going to continue this experiment so watch this space.