Greetings Forum Members,

The dash lights on the left side of the instrument cluster on my 1990 300E
stopped lighting and my alternator has stopped charging.
I have searched the forum for information and have learned that if the alternator charging indicator light bulb has gone bad the alternator will not charge the battery.
My question is, will a bad charging bulb cause all the lights on that side of the instrument cluster to go out also?
I have removed the charging bulb, it looks good. I will replace it anyway later today. I hope that it solves my problem.
Does anyone have experience with this issue?
Any help would be most appreciated.


Thanks,

Knarf

__________________
72 350SL #69
73 450SL Parts Car?
78 450sl Parts Car
79 450SLC - Sold
1985 280sl
87 190E 2.6 - Donated
90 300E-Junked
97 E420

I've not taken apart many W124 clusters, but they seem to nearly identical to the W201s that I've repaired.

Loss of power to the left side of the cluster typically indicates that there is a break in the grounding of that cluster with the central cluster. The ground is established via a metal to metal contact between the two. Over time, vibration and age can cause the contact to separate. On a few clusters, there is a fuse installed on the backside of the cluster that may have burned out.

Many times, you can check for a small ground break by hitting the top of the dash with your hand and see if the shock temporarily establishes the ground and the indicators work. The fix is to run a single jumper wire to re-establish the ground.

MTI,

Thanks for jthe reply.
Now it's just a matter of me releasing the speedometer cable to check out the rear of the cluster.
I can't get a good grip and it seems to be screwed on very tightly.


Knarf

__________________
72 350SL #69
73 450SL Parts Car?
78 450sl Parts Car
79 450SLC - Sold
1985 280sl
87 190E 2.6 - Donated
90 300E-Junked
97 E420

MTI,

I've removed the cluster, taken it apart, cleaned the ground contacts including bending the small ground contact tab to make a better connection to the left side of the cluster. I will be installing the cluster tomorrow to see what happens.


knarf

__________________
72 350SL #69
73 450SL Parts Car?
78 450sl Parts Car
79 450SLC - Sold
1985 280sl
87 190E 2.6 - Donated
90 300E-Junked
97 E420

Not sure if this has anything to do with your problem but there is a tiny fuse element, part #2015460025, in the instrument cluster. It's behind the cluster, the part that you see looks like a little bulb socket but it's red, it's the only red one back there. It fits into the rear of the cluster like some of the tiny bulbs. I forget which lights in the cluster it affects.

Ron In SC,

Thanks for the reply.
I checked that fuse and it looks good.
I'll report back after I reinstall the dash cluster wiring and turn the ignition key on.


knarf

__________________
72 350SL #69
73 450SL Parts Car?
78 450sl Parts Car
79 450SLC - Sold
1985 280sl
87 190E 2.6 - Donated
90 300E-Junked
97 E420