Courtesy light delay fault

[Harry Lake]

The other day on the way home the interior light in my MY93 CSE suddenly switched itself on. Not what our American friends and enemies would call a Big Deal, you might say, but I fear the consequences may be serious (financially).

As the light wouldn't go out when I told it to, I switched it off (by switching the switch to the middle position = off at all times; this is a three-position switch: 1 on at all times, 2 off at all times, 3 off unless a door is open or was shut less than 15 seconds ago).

I then, of course, switched on the alarm.

About a minute later the alarm went off.

My own theory is that the switch-off delay device has conked out and that this somehow leads to a) the light not going out and B) a fluctuation in current which causes the alarm to go off.

The problem also affects the light in front of the mirror, but the door switches appear to be working properly as the lights in the doors themselves come on and go out as they should.

Where is the delay device, in the switch unit or one of the lamp units - or somewhere else? Yesterday I tried it again and for a moment it worked as it should. Then I *think* I heard some clicking from the dashboard, near the intake fan for the ACC interior temperature sensor. Is it in there somewhere?

Cheers,

Harry

[mark e]

I'm pretty certain it will be the delay relay that has failed. I can't remember the exact one, but it's one of the relays fitted behind the glovebox and fuse panel. You need to remove the glovebox to get at it then undo two screws to allow the relay panel to drop down. IIRC, it should be labelled. If you pull it out and don't replace it you simply lose the delay function.

It's a particularly annoying feature of the way most alarms seem to be "integrated" in to 9000s. A couple of diodes would solve the problem...

[Harry Lake]

Originally posted by Mark E:
[qb]I'm pretty certain it will be the delay relay that has failed. I can't remember the exact one, but it's one of the relays fitted behind the glovebox and fuse panel. You need to remove the glovebox to get at it then undo two screws to allow the relay panel to drop down. IIRC, it should be labelled. If you pull it out and don't replace it you simply lose the delay function.
... [/qb][/b]

Thanks Mark. That is certainly where I hear clicks when the relay operates. For operate it does, again - just like that! I was parking the car after a trip and it suddenly buzzed at me briefly, since when it has worked. But obviously I'm going to have to get a replacement for when it happens again, so your info is much appreciated!

Cheers,
Harry

[redrocket]

the relay is in poiston m in my 89 9000i n/a in the glove box under neath the fuse board

[Harry Lake]

The problem went away of its own accord but has now returned. Unfortunately I have found that removing the relay has no effect. Next stop: door switches, then ceiling console switch. Or should I start with the ceiling switch?

NB The light works fine but simply doesn't go off. If I turn it off manually, the car alarm triggers about half a minute after locking the car. So at the moment the car is not alarmed, unlike me.

Harry

[Mark in Ireland]

My interior light comes on by itself also so I leave it in the off position and as my alarm doesn't appear to monitor voltage/amp my alarm works okay. I suspect a door switch but haven't had time to check.....when you find the cause give me a shout!!!

[Derek]

Harry,
The lamp is supplied with +12V from the fusebox and is illuminated by supplying a route to earth. Depending on the position of the switch it is either earthed by a door switch or the time delay relay. With the switch in the central position no circuit is made and the lamp should remain out.
So, if it is light all the time irrespective of switch position there is either a short to ground in the light unit or in the switch.
Incidentally the door switches operate two seperate circuits , the roof light and the door lights which are quite independent.

[Derek]

Mark,
In your case either one of the door switches is permanently grounded or the time delay relay is faulty.

[Harry Lake]

Originally posted by Derek:
[qb]Mark,
In your case either one of the door switches is permanently grounded or the time delay relay is faulty. [/qb][/b]

So does that apply to me too?

To reiterate:
If positions are 1 On at all times, 2 Off at all times and 3 On when doors open, then:

In position 1 the light is on.
In position 2 the light is off, but the alarm goes off, so I can't use the alarm.
In position 3, the light is on all the time, but dims momentarily when the ignition is switched on (at which point it should go off, if still on).

Removing the relay makes no difference.

All five switches appear to be fine - no visible corrosion or broken connections.

Harry

[Derek]

I got the idea that your light was on at all times irrespective of the switch position. I'l have to have a think about it again. Hmm...