W115 Dash

[Niels]

Hey guys, I'm having trouble with the dash lights on my '71 W115. They won't turn on. I have gone through the fuses and pulled the dash out to check the globes and there's no issues with any of them, so has anyone got any ideas on how to fix this? It's all the speedometer and gauge lights that don't work, while there is no issue with the hand brake lights etc.

[Adv_rider]

Research for "rheostat"... There are severas threads and DYIs

[meltedpanda]

and then just bypass it ...by jumpers

[Pooka]

You can pull this part and clean it. Radio Shack sells some electronic cleaner in a spray can that works great on this part.

This is almost without a doubt the rheostat. The good thing about this is that it is easy to get to and easy to repair.

[Adv_rider]

Originally Posted by meltedpanda

and then just bypass it ...by jumpers

Originally Posted by Pooka

You can pull this part and clean it. Radio Shack sells some electronic cleaner in a spray can that works great on this part.

This is almost without a doubt the rheostat. The good thing about this is that it is easy to get to and easy to repair.

And then if the rheostat is jumped and the dash illumination doesn't work? .. but the other indications like parking brake, low gas do work.. what to check?

[Palolo]

Things like brake, alternator, fuel reserve, high beam indicator, etc., are just that, they are "indicators" triggered by their respective senders or switches, and not tied in to the "cluster illumination".

I would break out the multimeter and see if you are getting +12V ahead of the infamous rheostat, and also downstream of it, then start checking the grounds.

For all you know it is a fuse. Check those too. Rotate, take out, reinstall, rotate again.

[meltedpanda]

or one of the traces has cracked, use the multimeter , you will find it , and the dash pos must ground to the metal frame, a lot of times when you remove for some reason that ground does not work, I and many others run a separate ground off the post to the body frame under the dash

[bricktron]

if several cluster indicators have stopped working at the same time, a faulty ground does seem like a likely failure point.

[meltedpanda]

had that issue on a W115 and a W123

[Adv_rider]

Originally Posted by meltedpanda

or one of the traces has cracked, use the multimeter , you will find it , and the dash pos must ground to the metal frame, a lot of times when you remove for some reason that ground does not work, I and many others run a separate ground off the post to the body frame under the dash

This!

Tomorrow i will chek it.
Just ground to any metal part on the back of the cluster? Or what exactly is the post? ... The metal rail on the back?

[meltedpanda]

the pod has a metal frame IIRC so use that and a good mounting screw somewhere under the dash

[Adv_rider]

Originally Posted by meltedpanda

the pod has a metal frame IIRC so use that and a good mounting screw somewhere under the dash

Melted, what is the pos or pod you're talking about?

Today I ground a cable from the cluster back and still no light ..
Fuses are ok, I'll need to check the lines.

The car lights turn on even without the key... Is this std?
Also, do I have to turn the key for the dash to illuminate or turn the car on?

- I also don't have any dash light...

[meltedpanda]

lights on key off - yes
key on - idiot lights light - yes
dash light general illumination should come on whenheadlamp switch is turned on - often this is dash rheostat that is the culprit, by pass it or try to clean.

the pod is the "dashpod" and there is a metal frame around it ( may be under rubber) that is what you ground to with the extra ground
with the dashpod grounded - Have you confirmed 12 v in the sockets? and that bulbs are good?

[whunter]

http://www.peachparts.com/shopforum/vintage-mercedes/227013-w115-electrical-woes-instrument-cluster-lights.html

Welcome to the fleet 1976 W115.114 "300D" dark Green



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