300SD speedometer & Cruise Ctl

First I'd like to thank mercedesshop for the quick responses to my questions, they have been very, very helpful.
Now I have a speedo question. Speedometer & Cruise were working fine, then while driving the speedo went dead. Not really sure where to start. I know there is a control box under the dash, and the wiring harness that goes to the tranny. But after reading the postings, there seems to be several other areas involved as well. If someone could offer up a starting point to begin eliminating possibilities I would really, really appreciate it.
Thanks for your time,
Peter Kalloday

------------------
Wing_Nut
82"300SD

[Benzmac]

Look very carefully at the fuses. There could be a hairline crack in one.

------------------
Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I've already replaced all the fuses, and I've cleaned the contact points with a light grit sandpaper. I've got good power on both sides measured with a volt meter. I appreciate the information, but I do believe it is something a little more involved.
Once again, thank you all for your time.
Peter Kalloday

------------------
Wing_Nut
82"300SD