[Vollblut]

The interior light switch in my 92 900i won't stay on. It won't turn on when I open the doors and I need to press down on the rocker in order for the light to come on.

Is this switch a straight swap if I buy a new one? Do I just pry out the old one and press in the new?

Thanks!

 

[heavy_t]

If you take the centre console out you might find it's just a loose connection or something. I think the connector works its way loose over time.

I've had a couple of cars where I've had the same problem, but in this one I took the console apart for something else and it worked fine after I had reassembled everything...

 

[philjohnhb]

You don't need to remove the centre console, the switch will prise out with care. The other possibility is that the two plunger switches in the doors are siezed.

 

[peva]

I agree. I would money on the door switches being seized or corroded. Take 'em out and clean 'em. Don't need to take the switch out. Can't really see that failing.

 

[shaverjeff]

Interior light switch failure can be common.
Had the same problem on my vert. The switch connections are made from copper which tend to corrode. Luckely the switches pop out quite easily as mentioned.
I was able to clean mine with a bit of vinegar and sandpaper and now it works great.

 

[heavy_t]

I've had a couple of 900s where you have to push the centre console switch quite hard right down into the '1' position for the light to come on. I think that's what he means.

Just ignore my over the top advice about removing the whole centre console please. ;oops:

 

[Vollblut]

I've had a couple of 900s where you have to push the centre console switch quite hard right down into the '1' position for the light to come on. I think that's what he means.

Exactly what I meant. Do you think taking it apart and cleaning it will solve this? TIA

 

[saabreur]

Corrosion on the copper is one possibility, another is the alignment of the copper strips inside the switch body. They get misaligned with slight side pressure on the switch, but are easily re-aligned, lots of trial and error! You can test alignment before assembly using a continuity tester; centre pin is power in, IIRC, and switch connects centre pin to left or right pin depending on rocker position. If no connection, adjust position inside and retry. Take switch apart very carefully and look at how strips fit. It's not exactly intuitive. But worth the little effort it takes, I found!

 

[Vollblut]

Corrosion on the copper is one possibility, another is the alignment of the copper strips inside the switch body. They get misaligned with slight side pressure on the switch, but are easily re-aligned, lots of trial and error! You can test alignment before assembly using a continuity tester; centre pin is power in, IIRC, and switch connects centre pin to left or right pin depending on rocker position. If no connection, adjust position inside and retry. Take switch apart very carefully and look at how strips fit. It's not exactly intuitive. But worth the little effort it takes, I found!

Thanks for this. First item on my list after the -gulp- headgasket is replaced!

 

[buzzook]

Reviving old thread - further questions

Have read thru all the interior light switch threads, and cannot get my 91 5dr door switches to operate the interior light....

...I took the switch out, found the connector loose - pushed it on firmly and voila, Pos 1 works (which I assume is the 'manual switch' to operate the light with doors closed)

....Pos 0 nothing works (assume this is correct) but...and here's the bit I need help with....on Pos 2 the door switches don't activate the light, it stays 'on' like on Pos 1...pushing door switches in and out makes no difference...

Also, I can hear a relay 'tick' when the door buttons are pressed individually (ie: only one door open at a time) so assume they are all ok if current is flowing to enable the relay....but...

Is there some 'trick' to adjusting the copper 'pitchfork' inside the switch?

Seems to me that the righthand arm should connect first (there is a ramp in the plastic surrounding the copper electrode on the switch body)...

..and the middle arm seems it should only connect when right forward, but beyond this I'm lost...

Any tips or clues?

Could the relay be an issue? Is there a fuse I should check?

[NB: Do not (yet) have a 'Bentley', and have been unable to find any info on the rear seat fusebox layout..]

 

[AUSSIE900]

The operation you describe sounds fine .

O is no interior lights

1 is turned on by door switches and turned off by door switches with a *courtesy* time delay relay

2 is a simple ON .... not door switch or timer relay related . In posi 2 your lights will stay on for the duration of your battery
Your rear seat fuse box should have a sticker showing what fuse is what

 

[buzzook]

Ahhhhhhhh...!! That's the 2 key pieces of info I needed.....

- "TIME Delay" relay....

- doors switches off Pos 1....

Just tried it again (with some patience, this time...;oops and guess what...it's working fine!

Didn't realise there was a time delay on the door switches..how cool ;ol;

My old Merc had that facility and I thought it was excellent, as I could shut the door and find the ignition switch with the light still on.

Liking my Saab even more... :cheesy: