Hey folks. I have an '89 e350 (school bus) with a 7.3l IDI and an e40d tranny. I've had some tranny issues in the past (bad tach sensor, etc), but I've never ever been able to pull codes. I tried a SCAN tool, as well as the good ol' voltmeter method. There's just never been any readings in my test plug, even when this OD light is blinking. Does anyone know what might cause this. EEC problem? Thanks in advance.

 

Really, no one?

 

I use a test light, not a DVOM.
If that doesn't work, then you have a bad wire.