Hi guys,
I've swapped my truck for my dads 1991 250 Roadtrek Conversion van with 318 so I can camp out for what's left of the summer. There are about 70,000 miles on it.
There has been an ongoing issue where the speedo, cruise, O/D, and odometer are not working. My dad has been through this before and replaced the speed sensor and rebuilt the odometer to get things going again. This time my dad had the speed sensor changed with no luck so he sent the dash out to be checked where it was rebuilt and it turned out OK.
In the end he mounted a GPS on the dash to drive it to my place (1000 km) so it's been run for a while since it was worked on. I just checked the codes and I'm getting 12 and 15. Is it possible that these are old codes or is the van telling me it's still got a speed sensor problem?
Another issue is that the van stalled out after a long run on the highway. Apparently it tends to do this when you run it slow after a good run. I'm not sure this is related but I thought I'd put it on the table.

Any ideas on what I should do next to get the speedo working?

Thank you, Steve

 

Hi again,
I worked on the van a bit tonight. Is there any chance the VSS or OD is picky about voltage? I am only getting 13.7 Volts when the van is running at any RPM. I have figured out the issue with voltage but will spare you the details...just wondering if I'm on the right track.
Also, how do I get to the stuff under the battery? The battery had acid on top of it so I need to see if it was leaking down there onto stuff and these Dodges are way tighter than my 1987 E150 was.
Steve

 

It sounds to me like you have several issues that are not related. If you read older posts, often a common thread is poor grounds, or grounds at various points on the engine that have corroded over time. Having an older van with so few miles makes me think that under use has allowed corrosion to effect a number of things, including the stalling issue.
check out this post for rough run issue
https://dodgeforum.com/forum/dodge-r...n-the-iac.html

also do a search for ground locations for this engine

 

I had a part success today as I was able to determine that the VSS worked outside of the transmission and that the new VSS was not installed properly. I yanked the gear out of the transmission (it turns out this loses a bit of fluid when you do this...) and found it was a #37. I then put it back in, clocked the outside dial so that the range for #37 was at 6 o'clock, and it started working again. I now have the O/D, speed, and odometer working again.

I agree that there is a grounding problem too because the Temperature and Fuel read low all the time. I cleaned a few of the firewall grounds and the PCM mounting bolts but that didn't help. I'll try to find where the battery ground goes tomorrow. This is a conversion van with a big sewer pipe and running boards plus it weighs about 1 million pounds so it is NOT easy to get under it.

Steve