I recently bought an 83 300SD. This morning, I started the car up
and there was no movement on the instrument panel. The glow plug
light worked as expected but the battery light stayed on longer than
usual and the Temp, Fuel, Oil Pressure, Spedometer and Tachometer
stay completely flat. It runs as usual and I couldn't find anything else
in the car not working. It seems to have started when I shut the door
so I initially thought I just jarred some kind of wiring harness loose
but I'm not sure it started right then since I wasn't paying particular
attention. Anyone have any hints?

Thanks,
Carl

 

Not sure if this will help you but clean up the contacts on each end of the fuses. I had a tach stop working on an 85 190E, turned out to be a corroded fuse.

 

I got a little hint this morning while driving. I hit a large
bump on the freeway and the dash suddenly sprung to life.
Sadly, it died again after about 1/4 mile. It seems, in light
of this, that there must be a loose connector somewhere.

I'd like to get the instrument cluster out to see if that's
where the problem is but I can't see any obvious way
of getting it off. Am I correct in assuming that I need
a special tool for that?

Thanks,
Carl Flippin

 

The cluster should just pull out, it has a rubber sleeve holding it in. My guess is the tepminal connector on the back is loose.....tight back there!

 

Pulling the cluster is not bad. You can bend a couple of small hooks and use those to pull the cluster straight out, or the way I do it is reach up from behind the cluster and push out while working it with your other hand --- it pops right out. It took me longer to type this than it does to remove the cluster. I normally turn it a little to the left and unscrew the speedometer cable. While you're in there spray a little PB Blaster in the speedometer cable, if it's not making a noise yet it will. I put a wadded up paper towel under the cable and spray a litle bit, wait and spray a little bit more and wait again ---- then repeat a few times, you'll be glad you did. NOTE!!! Be careful with the left side because there is a small oil line for the gauge.

Tony T