Hello ..

I have a '91 D250 that has developed several problems all at once. They are a non-functioning speedometer, no air heaters or wait-to-start light, and no overdrive. There is also no voltage on the KSB valve during cold start. I've checked just about everything I can think of; fuses, fusable links, ground on the distance sensor, cleaned the engine grounds, verified power and ground to the ECU, etc ... Voltage regulator and charging seem to be OK and the truck starts and runs fine otherwise.

Anyone have any ideas?

Thanks in advance!

Reiney

 

The non-fuctioning spedo makes me think about my 97 Intrepid. I had this happen, and it also effected my shifting. later I found there wasa speed out-put sensor along with a speed in-put sensor on this trany. I don't know if this was done on your year truck as well, but if so, that may be an area to look. Is your speedo gauge eletronic or cable deriven? Good luck!

 

Thanks Kurt,

The speedo is electronic. I would have suspected the sensor but the air heaters conked out too and they should be operable even if the truck isn't moving.


Reiney

 

I'm no diesel spert but a quick look at awiring diagram seems to point to the Air Heater Controller? Possible ground at the controller, power feed from the ignition switch, bad ignitionswitch/connector/wiring? Thermistor goes to ground?

[IMG]local://upfiles/21718/C81338AA25AF4DDBBD336093718737F8.jpg[/IMG]

 

Hey, thanks for the diagram! Just wondering what manual did that come from since it's not in mine. I'm still working on this a little at a time; not to much fun to be outdoors trouble shooting in the 15 deg. weather. I'm being hampered by the fact that I can't seem to even locate the darned controller; probably due to the extra stuff I have in there for the veggie-oil conversion.

Thanks again ..

Reiney

 

Try www.alldatadiy.com for a subscription. It will have a ton of info and diagrams.

 

There is a speed sensor on driver side of transmission that the speedometer gets its reading.On my 92 250 gasif the speedometers notreading than the transmission will not go into overdrive. I have to get under truck and tap on the sensor and speedometer usally starts to work and transmission will go into overdrive. I have replaced the sensor twice, replaced the sensor tower,checked wiringand still have this happen occasionally. I now take sensor off and clean with contact cleaner and it works for a while. Hope this helps.

 

http://dodgeram.info/tsb/1991/08-10-91.htm