How did I manage to kill my turn signals [280SEL]

[BoneStock]

Noticed that my front passenger parking light was out so I picked up a pair of equivilant replacement dual filimant bulbs at my local parts store. I've never had the front signals apart before so it took me a while to figure out that you just crack the cases apart. In any case I've now replaced both bulbs and both corosponding fuses [7 and 8] and even tried the old bulbs. the result is that I now have both parking lights but no emergency flashers or turn signals. If I listen carefully I can hear the flasher franticly flashing I quickly turn the switch off. Seems to me the flasher isn't 'talking' to the bulbs... but why? I tightened the 3 wire connector screws on each light base. Does anyone have the pinout for the lights for me to start trouble shooting?

Sorry for the long post, I apretiate your patience.

[BoneStock]

I don't like bumping up my own post but I'm desperate. I have been driving my new car since the mercede's turn signals don't work and I'm getting sick of it. I wana drive my Benz!!

Please give me tips which might help me fix my turn signals.

Clues:

-Both front bulbs replaced.
-hazards and turn signals make the flasher tick in the dash rapidly for about a second. While that ticking happens my VOM reads about a volt across the bulb wire.
-parking lights work fine

[MikeTangas]

Could the bulbs be in 180* out?

[Tomguy]

I bet your parking lights are super-bright up front, too.

If you look at the bulb, you notice there is only one PROPER way to insert it. There's two ways it CAN be done but only one in which it SHOULD. Inserting it the wrong way is a sure-fire way to have nonfuntioning bulbs. And unless you're paying attention when installing it, as there's a 50% chance of doing each the wrong way, sounds like you hit that 25% one of doing both wrong! Plus, sometimes they go in easier the wrong way!

In the pic, you can see one of the "nipples" on the base is lower than the other. This side goes in the side of the socket that goes down lower (closer to the contacts than the other). If you have the bulb in backwards, and both filaments worked, the thick, lower filament would light with your parking lights, and the thin one would be your turn signals. The thin (5W) filament should be your parking lights, and the thicker one should be your turn signal, when installed properly.

If you do put it in wrong, you might not be able to push down and turn it into place, it might sit crooked, or the bulb will be too far from the contacts (the lower one in the higher hole with the higher one not seated at all).

[BoneStock]

Oh boy, I should have added the 'mildly intelegent person inside' disclaimer lol.

I tested continuity from the bulb's actuall contact nipple to the wire terminal on the bulb holder. Also remember that I'm getting a very low electrical pulse at the bulb's terminal's them selves when I flip the signal on. My VOM seemed to think the pulse was around a volt [to rapid for it to really tell]. Should I pick up the flasher module? I looked in my factory service manual and as best I could tell, its part of the hazard switch!!! I sure hope thats not the case cause its gona be hard to get to.

Whoever comes up with the correct suggestoin is gona make one happy kid.

[Tomguy]

So you have no rear turn signals at all, either?

1 volt is too low, but a multimeter probably can't accuratley detect the voltage because it pulses too fast. Something I might try if I were you would be putting +12v to the front turn signal lead and seeing if the rear light is lit. That would be a quick way to eliminate the wires as the problem.

[BoneStock]

Yes rears don't work either. Good call, I'll try that and post the results. Thanks.

[speedy72t]

I'm a 108 junkie and have worked on a ton of electrical problems with these things. Very rare for the relay to die but it can happen. If you pull the bulbs out of the sockets entirely do the rears lights start working? Check ALL the fuses with the a test light, not a VOM. check the grounds on the tailights. Remember that the relay is designed to flash eratically if it thinks the bulbs are burned out. it's all load dependant. Until all four corners are working correctly the relay won't flash smoothly.

[BoneStock]

Originally Posted by Tomguy

So you have no rear turn signals at all, either?

1 volt is too low, but a multimeter probably can't accuratley detect the voltage because it pulses too fast. Something I might try if I were you would be putting +12v to the front turn signal lead and seeing if the rear light is lit. That would be a quick way to eliminate the wires as the problem.

If I apply +12v to the front turn signal element both the front and rear signals [for that side] light up. I tested both left and right and both act the same so the wiring in that respect seems fine. I realise its unlikely the flasher is out but where is it and how can I test it in car.

[BoneStock]

Originally Posted by speedy72t

I'm a 108 junkie and have worked on a ton of electrical problems with these things. Very rare for the relay to die but it can happen. If you pull the bulbs out of the sockets entirely do the rears lights start working? Check ALL the fuses with the a test light, not a VOM. check the grounds on the tailights. Remember that the relay is designed to flash eratically if it thinks the bulbs are burned out. it's all load dependant. Until all four corners are working correctly the relay won't flash smoothly.

I tested continuity of each fuse from holder tab to holder tab. with the key to 'on' I have power at fuses 1-6 and no power at 7-12.

As to your other questoin, pulling the front bulbs does not allow the rears to flash eraticly. Seems like no matter what I do, when I turn on the hazards or turn signals I hear a faint clicking in the dash for about a second and then it disapears. Does anyone have pictures of the flasher and or relay so I can try to find them? I think wiring and bulbs are good.

PS this car was a dailly driver for 2 years without problems. Currently the only electrical problem is the turn signals/hazards. Seems to point either to the flasher or relay. I'm open to ANY suggestoins though, ARG I wana drive the mercedes.

[speedy72t]

so neither the turn signals or the hazzards work? The way hazzard lights are wired on the 108s changed a lot through the years. I get the impression hazzard lights were a USA only requirement. I believe the relay is fairly cheap and located under the dash by the steering column. Follow the faint clicking whith the turn signals on to locate the relay. The hazzards may work in tandem with that turn signal relay. so replacing the relay may fix both problems.

[BoneStock]

Correct, neither hazards or directional flashers work. I took off the steering cover and this is what I see. In Picture 2 I can see a canister thing which resembles a turn signal flasher but I neither get any voltage from its progs nor do I hear it click when I turn on the flashers. The cliicking seems to be higher up.
1

2

3

[speedy72t]

I'm so jealous. I've been 108 less for too long. Probably my favorite chassis in the history of the auto. At least that I can afford. Start uplugging modules until the clicking doesn't click anymore. Then you will have found your defunct relay.

[BoneStock]

Originally Posted by speedy72t

I'm so jealous. I've been 108 less for too long. Probably my favorite chassis in the history of the auto. At least that I can afford. Start uplugging modules until the clicking doesn't click anymore. Then you will have found your defunct relay.

No need to be jealous, think you can figure out the turn signals? Then make me a offer. This is the straw that broke the camel's back.





On a more seious note, any Idea WHERE those relays might be? I can find relays under the hood without problems but without disassembling the dash I can not see any relays. HELPPPPP!

[speedy72t]

come on man. a turn signal relay and you are going to sell the car? you said you can hear faint clicking up in there. just feel around until you can feel the relay or start GENTLY unplugging things until it stops da clickin. I believe everything can be reached from underneath but sometimes you do have to take the speedo cluster out to get to things higher in the dash.