I just did a lot of reading and it appears that most speedometer problems are the VSS or ground. Does the VSS also run the odometer and if so where should I start looking. Some days the speedo works and others it does not but the odo always works. Ant ideas would be great. Got to love the Dodge electrical system. Thanks.

 

That's a bad speedo. They both work off the VSS so if the odometer is always working then the VSS is OK.

 

Are all speedometers the same? Gasser, Diesel etc. What years should be the same?

 

Years '90-'93 will work. Gas and diesel are the same, so are Ramchargers. Late '92 (build date 3-12 and later) and '93 use a more robust odometer section so you might want to look for one of those with mileage you like.

 

Thanks for the info, the search is on!

 

My speedometer is also intermittent at this time, sometimes it will work for months and then next time I start the truck it won't work so as soon as I get some time I am going to pull the speedo and take a look, I think I will pull the VSS and chuck it in my drill press to get a signal and then connect it to my speedo head I have a feeling that when I took it apart to replace the gears I may have caused a bad connection when I pulled the boards apart.
I have been using my GPS to check my speed.
Jim

 

Old thread I know but, I have the same problem as you do(did) Jim. My speedo quite often doesn't work but ODO and Trip meter still work as does the cruise control.

Did you ever figure out the cause?

 

Ttt

???

 

Not sure if anyone has found a cure, but mine has been doing this for a while now. After Im rolling a little bit, I can flick the trip meter reset **** a few times, or sometimes just push the **** in kind of hard, and itll start working, until it sits for a while.

 

The palstic gears in that dam speedo are crap. Mine went south on a '91 and I went to dealer for a new one. they had to send it to Dodge to replce it so they could set the numbers the same as the old one. You aren't allowed to by a speedo from a junk yasrd in TX. Anyway. the new unit lasted about 8 months and went south again. The odometers never went south. I finally replaced it with digital speedo from Dakota digital. I had a '90 that went south at 435k Truck is still being driven daily 15 years later. Must have a million or more on it by now. I drove it for 4 years after it broke and put on at least 25k a yr!