i have a couple question. I replaced me heather core yesterday in my 1999 Dodge Ram 1500. 5.2L V8

After following all the steps and getting the new heather core and and everything back together I noticed a few things. My ABS light now comes on. After driving it for a bit a also notice that my emergency break light comes on and my speedometer does not work properly. The speedometer at times goes to 120mph when I am only doing about 30mph. When I noticed that I pulled over put the truck into park to setup my GPS which will tell me my speed. When I started driving again my speedometer was a little more accurate. However this time it was about 5 - 10 mph under the actual speed. Any idea what might have caused this? Are there specific wires I should be checking to make sure they are properly connected? Any advice on this would be appreciated. Thanks

 

Make sure all grounds are back in place.

Dave

 

It appears the speed sensor died coincidentally. It is on the top of the rear diff and can be replaced easily.

 

I will go through and check all the grounds as that could be a possibility.

As for the speed sensor, I replaced that about 6 months ago. I guess it could be faulty but I don't think that is the issue.