Chrysler Repair: 87 lebaron digital dash, lebaron convertible, cv boot

Question
Hello Roland,

I just got this 1987 Lebaron convertible which is in great shape for the age it is. Now my Question is that my digital dash has gone haywire, when the vehicle is cold and I drive away lets say at speed of 50Km/hr the dash would show 25km/hr, as the vehicle warms up then slowly the reading on the dash goes up too when I go say 85 km/hr the dash would read 50 and so on But when the vehicle is hot it will never give a true reading , my wife was a head of me a few days ago going at 110km/hr in her car I was following her in the lebaron but the dash would only read 99km/hr. I'm thinking it is the speed sensor, and if so where would it be located.  

Thanks
Menno

Answer
Hi Menno,
The sensor is on top of the transaxle extension housing (the part from which the half shafts extend). If you look behind the engine from the driver's side you will see a wire that runs behind the end of the cylinder head and down to the unit located in line with the halfshaft, but on top of the housing. It is held in place by a single bolt, and it has an electrical disconnect. It is possible that its gear on the tip was damaged in the past if somebody removed the right half shaft in order to replace it or a cv boot without first removing the speed sensor. So you can probably find a replacement at a wrecking yard. Or you may be able to get just the gear from a dealer. I think the whole unit is around $100. You can test it by lifting up the right front wheel and put an ohm-meter across the two terminals of the disconnect. The reading of the ohm-meter should pulse 8 times for every revolution of the front wheel.
Check that out, and if it seems OK then I would suspect the dash itself.
I hope you enjoy the car.
Roland