[c900]

Curious to know how you might have upgraded/improved/fixed the lighting in the trunk/boot of your C900, and how you've addressed the issue of how easy it is to forget the light is on which can drain the battery enough overnight to prevent starting the next day.


I've just recently configured a solar panel, battery and rigid LED light strips (2 x 1 m, 2 x 0.5 m) in a tradies-type tool trailer I've been upgrading and I'm considering using a pair of the 0.5 m ones plus a customised switch setup to give a much better boot/trunk light for my 2.1 sedan plus be much more obvious when it's left on by mistake.


My idea is to use neutral-cure silicone to 'glue' the two rigid strips under the upper part of the body opening so there's little or no 'infringement' of space to get stuff in/out of the boot/trunk.


Then I'd replaced the factory light/switch thing with a little bit of metal with a LED-illuminated toggle switch.


I want the setup to be as discreet as is possible so to not look 'bogan'. As I intend to use the car as an alternative daily driver and I do shiftwork, good boot/trunk lighting is important.


With a hatchback C900 the same kind of thing would work but with different configurations of LED lights and switch to get the same kind of outcome.


Craig.

 

[jvanabra]

The light goes off when you close the trunk... how would it drain the battery?

 

[c900]

No C900 I've seen has any sort of boot/trunk light that is switched on/off automatically by opening/closing the boot/trunk of a sedan or hatchback config. Maybe the US-market ones got a different config for this?

 

[peva]

No C900 I've seen has any sort of boot/trunk light that is switched on/off automatically by opening/closing the boot/trunk of a sedan or hatchback config. Maybe the US-market ones got a different config for this?

All 900s have an automatic switch for turning trunk light off when you close the hatch. What car hasn't? Maybe yours is broken or has faulty wiring.
The location of the switch is not obvious. On the hatch it's hidden inside the latch cavity. So maybe 'cause you can't see it, you think you haven't got one.
It's only obvious/visible on the 900 vert.

 

[PabloRock]

I have a 3 position switch in my trunk light (93 S vert US). One shuts it off, the middle is auto, maybe the third is always on? (stupid option if it is. maybe in case your locked in the trunk?).



(I keep it off at all times because I tend to keep things open when I am working on it, which is more often than the driving it).

 

[jvanabra]

I think you have the wrong light there! The dome light has a three position switch (off/on/switched) but the trunk light is off/switched only. That's true all the way back to my '80.

A trunk light that doesn't turn off when the trunk is closed is a switch that has failed. Which I have only seen once, on an 1985 4-door.

 

[PabloRock]

You may be right. Just checked my trunk light again, and maybe it just feels like a 3 way. It kinda clicks in the middle, but maybe it's just old and sticky.

 

[peva]

You may be right. Just checked my trunk light again, and maybe it just feels like a 3 way. It kinda clicks in the middle, but maybe it's just old and sticky.

Just checked my vert and hatch. The trunks have the same light unit with the same switch. There are two positions; off and auto. You can probably convince yourself the middle is a setting, but it's not.

 

[jvanabra]

FWIW, on my SPG I used self adhesive LED strip lighting run along the speaker shelves and powered by the original wiring.


https://www.superbrightleds.com/cat/flexible-led-strip-lights/filter/LED_Color,White,136,4627:


I ran a "link" (soldering required) between the left and right side of the car under the floor of the trunk. 30 minute install, lit the trunk up light daylight. I keep meaning to do that again on my '85 but haven't gotten around to it.

 

[Jim Mesthene]

Older cars had the 3-position switch, one position was on-all-the-time.
They changed it to 2-position because people used to kill their batteries all the time.
I forget what year it changed.

 

[c900]

The trunk/boot light does have three detent positions but it's only off, or always on. Never worked out why Saab configured them like that.



The main interior light has three genuine settings - off, always on, or switched the doors.


The festoon light draws about 0.9 amps from the battery. Over a long period that's quite a lot of parasitic current drain.


Craig.

 

[peva]

The trunk/boot light does have three detent positions but it's only off, or always on. Never worked out why Saab configured them like that.

They weren't configured like that. They just use the same components and the manufacturer left the centre contact out in this case. Simple economics

 

[c900]

I'm yet to figure out where the switch or contact assembly is for any sort of 'auto' function to work for controlling the trunk/boot light.

Putting that aside, has anyone actually created an auto-off feature for that light using something like a machine limit switch mounted so that shutting the boot or trunk operates the switch?

 

[jvanabra]

There is a switch inside the latch that cuts power to the light. It's there on all cars. Look at the wiring diagrams - it is not possible for the light to be on with the lid closed.

 

[jvanabra]

Note the indicated text:

"The luggage compartment light is controlled by a luggage compartment light switch located beneath the left trunk hinge on sedans and beneath the striker plate on hatchbacks."

Note the indicated component in the diagram, 56, and its interruption of the light's connection to ground.

Note also the diagram doesn't distinguish between years - this diagram is applicable to at least all 86+ cars, and AFAIK back to '80 or '81. It also doesn't distinguish between localities - it's true for cars worldwide.

There's not a need for a limit switch... it's built into the car. If yours doesn't work properly, it's either been modified or mis-installed or damaged. I promise.

 

[Jim Mesthene]

On the sedan, look for the switch above the left hinge by the bottom of the parcel shelf.
If the car has a SAAB alarm, the hood switch triggers the alarm by turning on the trunk light.