(91 Dakota with 5.2) Ok guys, I’ve have a troubling issue. My check engine light is not on but when I put it into diagnostic mode it flashes code 15. My cruise control does not does not work at all anymore, a few months back when I set the cruise the truck would continue to accelerate, now it has just stopped working all together. Also the truck will not stay in overdrive, it will continue to try to get into overdrive then kick back to 3rd. I have changed my speed sensor on the trans, my TPS, and the overdrive solenoid inside the transmission. All with no luck! Could it be some wires rubbing? Oh and recently the truck will stall out when coming to a stop!

 

15** No vehicle speed sensor signal

That's why your cruise doesn't work. Does the speedometer work?

 

Speedometer does work

 

Yes speedometer works fine, all fuses check good as well, my speed sensor has a cable and a wired connector, I’m wondering if those wires have good continuity, I cannot seem to find a good wire diagram to see where they go and I loose sight after they go on top of the transmission

 

Cable is for the speedo, wiring is likely for the PCM. Which is where the problem seems to be. Gonna need a service manual for your truck. Don't know if the 91 manual is drifting about around here, but, you can usually find 'em on Ebay for 30 or 40 bucks in PDF format.

 

Sounds like you may have a vacuum leak.