My 2003 T&C van has an issue where the output shaft sensor on the transmission fails and needs replacement (Common problem from forums). Because output and corresponding input shaft sensors are < $20 I replaced both. Both are magnet type sensors and read <600 ohms. Symptom is when sitting still speedometer fluctuates between 10 and 20 mph, making transmission think vehicle is moving and causing sensor fault. This is the strange part, if I do not have anything electrical running (lights, heater turn signals) everything is fine and Speedo is at 0. If I turn on anything - Speedo starts fluctuating and I get failure. I have replaced both sensors, Battery, and cleaned all connections connectors and terminals. When I put a DVM across battery I get 12.3 volts, crank engine and I get 14.5. When I induce failure I do not see any change from the 14.5 volt readings. I wish the alternator wasn't $200 and I would replace it to see what happens, but not sure this is the issue? Any ideas on what I could try?

 

bad ground some where its back feeding into that circuit

 

Chrysler Tech,

Thanks so much for the heads up.
Do you know if there are any grounds inside connectors on the transmission or are they all external to ring terminals attached to metal parts? Also, is there a web site where I might find a wiring diagram to ensure I find and inspect each ground?
Thanks again!!

 

it might not be one attached to the tranny if things like the lights when u turn them on that when the issue happens I would look at those on the side near the fenders on the engine.