Interior Lights not working

[tarheel]

Hello motoring friends.  I'm a brand new 280 SL owner and also new to this site.

I have a 1969 MB 280 SL and not one of the interior lights are working.  I see circular light lenses under the dash, and another oval light of sorts with a switch, but none will illuminate.

Checked the fuse and that is fine.

Any thoughts on diagnosis and solving issue?

I'm not mechanic, but is it easy to access said bulbs to replace?

I don't have a service manual (though eventually would like to save up and buy one), so any guidance supremely appreciated by this neophyte.

[Tyler S]

Hello Tarheel, welcome to the site and congrats on your new purchase.
Circular light lenses under the dash is not original to the car. The only "dome" type lamp originally installed is the ovular lamp in the center dash pad.
If the bulb is good, try spinning the fuses in the fuse sockets under the hood. These can become corroded and loose conectivity. The lamp is also connected to the door jamb switches. Does the glovebox lamp work? It is on the same electrical circuit as the dome lamp. Also do you get a red light on the instrument cluster when the drivers door is open?

[tarheel]

Hello and many thanks for your guidance.

Under my dash there is a section of black Frigiking for vents.  Under this refrigeration vent section are 4 perfectly circular clear lenses, which I assumed were lights that should open when doors are opened.  Are these not lights?

The ovular courtesy lamp you mentioned is working but a bit squirrely - the only way it turns on is if I move the switch in between positions 1 and 2.  I assume I need to buy a new one, as the lens is partially cracked anyway. 

Yes, I do get a red light on the instrument cluster when doors are open.

Shouldn't there be lights behind the gauges?  My interior is completely dark / not illuminated when driving at night at that just doesn't seem right to me.

Thoughts?

[tarheel]

Also - yes, glove box light working perfectly.

[Tyler S]

The clear lenses on the ac unit are actually access points to get to the 4 mounting screws. Not lights.
The instrument cluster lamps are controlled by the dimmer rheostat knob in the center instrument cluster. Turn it clockwise to brighten the lamps. The headlamps or parking lamps need to be on. It is possible the dimmer switch is bad as it is a common issue. Sometimes just exercising the dimmer will make it work again. Otherwise it could be the bulbs. Either way it is a lengthy process to repair. The tech manual has a procedure. There are also lamps tied to this that illuminate the heater controls. 

[tarheel]

Hi:

If it is not too inconvenient for you, is it possible to obtain a "night" photo showing all possibly- illuminated dash components illuminated?

I do not recall seeing a central dimmer rheostat knob, nor do I see one in the Owners Manual diagram.  I am going crazy?

I see you have a 1936 Ford.  You may be interested to know I am also working with my father on a 1935 Ford 3-window (not the common 5) Coupe.

Keep on motoring my friend.

James

[Jonny B]

The rheostat knob for the dash lights is located at the bottom of the central cluster of instruments (oil pressure, water, fuel). If the knob has somehow managed to disappear, there should be the tell-tale hole for said knob to be installed.

There should be some photos of the dash lights posted on the site, try using "LED light" in the main search function.

Here is a link that has a good shot of the dash lights
https://www.sl113.org/forums/index.php?topic=19084.0

Scroll down to 49er's post and he has posted the shot.

[66andBlue]

Hi:

If it is not too inconvenient for you, is it possible to obtain a "night" photo showing all possibly- illuminated dash components illuminated?

I do not recall seeing a central dimmer rheostat knob, nor do I see one in the Owners Manual diagram.  I am going crazy? ..

Take a look here, #9 is the rheostat: https://www.sl113.org/wiki/Electrical/DashboardInstruments
What kind of owner's manual do you have?

[tarheel]

My error - I was looking under the dash for said dimmer knob.

Unfortunately, now that Ive found said black knob, Ive discovered it simply does not turn.  Does it need to be pushed in or pulled out to turn?  I don't want to use too much force for fear of breaking the knob, but it certainly does not turn in my car.

I suspect this is associated with the reason my dashboard gauge lights are not illuminated. 

Likely the rheostat needs to be repaired or replaced per tech manual in this website.

Any final thoughts before I drop off at the mechanic's to make this repair?

[Jonny B]

You only need to turn it, there is no push or pull.

[66andBlue]

.... Likely the rheostat needs to be repaired or replaced per tech manual in this website.
Any final thoughts before I drop off at the mechanic's to make this repair?

Removing the instrument center cluster is not a trivial job, very time consuming even for a technician who has done it a few times.
If you have no other reasons to take the dashboard apart you might wait and just short the rheostat as described here:
https://www.sl113.org/wiki/Electrical/Rheostat
It will also tell you whether any bulbs are burned out.

[pj]

I'd like to discuss how difficult it is to work on the dashboard. Tarheel isn't the only one who has been flummoxxed by this. Obviously the original designers weren't thinking about crazy enthusiasts trying to keep things perfect 50 years later. So has anyone tried some kind of modification to the dashboard that makes the whole thing hinge away or open somehow? Then you could easily access the gewerkens for maintenance.

My car is being rebuilt and all the sheet metal is open right now, so if there's an improvement that could be made, now's the time.

[Tyler S]

Yea its too bad the designers didn't make the binnacle cover easily removable and have an access plate/hole underneath it.

[66andBlue]

Peter,
a real "Pagoda lover" just has to have a slightly masochistic trait!