1985 300sd
I'm having a problem with getting my speedometer working. I checked for signal, power and ground. They all checked out. So I replaced the speedometer head and the new one worked for a few weeks but the needle kept getting stuck and after trying to figure out what was making it get stuck it stopped working. So I replaced the unit with a speedometer that looked good. Now I'm getting nothing, and I re confirmed power, ground and signal. Anyway does anyone have any ideas of what else I should check? I'm not sure if this matters but I by passed the tach signal through the egr control computer recently. Any tips would be greatly appreciated