Sailorman2005
New Member
I have a 94 Dodge Dakota where the tachometer was failing. Upon startup the needle would float and then go full clockwise deflection, settling on the overdriven section of the meter. I pulled the old drive module from the back of the instrument cluster and began troubleshooting for bad parts and traces. I found Q2 and Q3 open on the collector side. C5 was reading 60uF vice 68 out of circuit. Not too bad for 20% tolerance. My issue is I have no datasheet on the 14 pin DIP and could not find this part anywhere online. The drive board part number is 4375410. It is a common board used in many Chrysler vehicles of the 90's. However, finding a good working one is sketchy at best. I would like some input on how I can test this board for a good input/output utilizing the ecm signal for tach. However, i do not know if this is just a 5v signal with an alternating squarewave or something else. If anyone have experience or knowledge on how to best test this circuit board I would be forever grateful. I will attach a diagram of the only schematic I could find. According to the repair manual the ecm sends a signal with the following for calibration reference.