1990 Chrysler New Yorker speedometer

Other Category problem
1990 Chrysler New Yorker V6 Front Wheel Drive Automatic 78.000 miles

My speedometer works fine but the mileage indacator does not, I have just bought this car awhile back and had alot of brake repairs and sheet metal replacement on front end where eldery gentleman hit a dumpster, thought had foot on brake had it on gas, just a front fender and hood and grill. From the looks of it this is a electracal output sensor not a cable, Could part of it be bad and not the other part?Not a real dummy here on cars, Have built and still race a NHRA Super Comp Dragster plus build transmissons to help with racing exspences, Retired after 35 years as night supertendent at a papermill and seen lots of breakdowns that seem unrelated.
thanks
Bob