Little light behind headlight switch? - PeachParts Mercedes-Benz Forum

sean 300D · #1 07-19-2002, 02:12 AM

Hey!..I've gotten every single light in the interior of my '81 300d working except the little bulb behind the headlight switch. I pulled the knob off, replaced the bulb (with several diff. ones to no avail), cleaned it out with good quality contact cleaner, then a blast of air...still won't work...Then, I took the lower panel off...looked up in there and all wires/contacts etc. look good and clean...Then, I used a tester and couldn't get any indication of power to the little contacts inside...but you know how those things can be...I know, I know, I'm micro-managing and being picky...but I really want all the lights to work...Anyway have any exp. in replacing a bulb behind this switch, and then not having it work????..

anyone?

thanks
sean

The Warden · #2 07-19-2002, 03:15 AM

You mean there's a light behind the switch?

What exactly does it light up? And how do you get to it?

Thanks in advance

sean 300D · #3 07-19-2002, 11:23 AM

Warden...there's a little bulb that illuminates the orange colored circle on your headlight knob. You just carefully pull it straight off to get access to it...I've tried everything to get it to work...Like I said, the wires all contacting the switch look good and clean...I can't get any power to it with a tester. And yes, I am turning the headlights on, then plulling the knob off to do this testing. I didn't know it had one either until the other day. I was driving an older 450SL and noticed the switch illuminating...hummm...

any ideas...?

sean

Arthur Dalton · #4 07-19-2002, 11:48 AM

I believe that lamp is the rear fog light indicator.

Pull knob all the way out and to the fog lamp position

84300DT · #5 07-19-2002, 12:16 PM

i cud never get that baby to work either...

sean 300D · #6 07-19-2002, 12:26 PM

Arthur...I tried pulling it out to the fog lamp pos. thinking the same thing..I don't know...elec. gremlins are a real pet peave of mine! But, now that you say it, I'll bet you're right...as there is, to the best of my knowledge, no indicator in the inst. cluster to tell me the fog lights are on.....hummmmm?

I don't want to go messin' with all the contacts on the back of the switch...kind of along the lines of the "if it works, don't fix it" catagory on that one...

I hate giving up...but I may make an exception...

later
sean

Arthur Dalton · #7 07-19-2002, 12:39 PM

Some have 2 notch pull posistions
The first is for front fogs, the second is for rear
Euro rear are only on the driver side/rear and some US don't have a lamp in that circuit, but may still have the socket..
Try one more pull notch..

ck42 · #8 07-19-2002, 12:50 PM

Ahh...so that little orange dot *IS* a lamp!!

If it is indeed just a rear foglight lamp....it soon WON'T be

I'll just rewire things a little to get it to come on with the rest of the interior lights.

sean 300D · #9 07-19-2002, 02:08 PM

I'll bet you are right on that one!...came home for lunch...pulled it out, no light...It will go out 2 clicks though. My car, being an american model, for sure, probally doesn't have the rear foglight feature...AND....I looked up behind at the switch itself again....AND...there's one (1) receptacle that remains empty (no wire going to it)...and it looks like there's never been a wire contected to it...Would that be the rear foglight option..and if so...mystery solved I just don't have it...

BUT....

I took out a burned out bulb that was there b4??????

explain spock..

sean

#10 07-19-2002, 06:51 PM

The only one of those little orange dot I've ever seen light up was on my 450SE which was a Euro car. I tried messing around with the one on my 300D and no avail. Doesn't look like there ever was a bulb in there, though the socket is there.

You probably could trace the bulb contacts to the correct posts on the switch and connect it to the front foglight circuit.

sean 300D · #11 07-19-2002, 07:01 PM

The only one I've ever seen light up was on a '75 450SL the other night..which prompted this whole thing to begin with..? Do you supp. the PO tried to put a bulb in there too at one time??..to no avail???...It looked like a nasty 20 yr old bulb that I pulled out...or, maybe they all come with that bulb in place, yet not wired for the rear fogs????

Will always be a mystery to me, I guess...

sean

Holson Adi · #12 07-19-2002, 07:57 PM

I don't think the bulb was ever there in a US car not equipped with a rear fog light. My W124 230E does though because it's not a NA-spec car.

#13 07-19-2002, 09:35 PM

My 83 300D switch lamp works as Fog Lamp indictor (On). It's on when the fog lamps are on. The light on my 84, which I have had for a only a short time, is not working and is on my list for repair.

The Warden · #14 07-20-2002, 01:56 AM

What's the purpose for rear foglights?

I noticed that the innermost bulb holder is empty on my car's taillights, and doesn't appear to have a positive lead. I assume this is the location for the rear foglights. How difficult would it be to get a lead in there for maybe a second set of brake lights or running lights? May as well make use of the spot, eh? And I don't even really use my forward-facing foglights very often.

Be nice to get the knob light working with the front lights, though...

omegabenz · #15 07-20-2002, 03:34 AM

Your car is older so it didnt have the fog light in the rear. They started doing that in the early nineties (wiring us and euro cars the same so that the rear fog light will turn on).

The orange dot will illuminate if you have rear fog lights hooked up and they turn on. There is another bulb on like that 87 300es that lights up the outside bezel to show what position you are in. I havent checked the W123 cars yet. Someone let me know on that?

I was thinking of wring up rear fog lights, but I couldnt find any of the same contact connectors for the rear. I might spend the time some day, but for now, I dont want to run the wires from the front to the back.

Austin