4R70W Overdrive Switch

[Toddml]

I have a 4R70W with an overdrive switch that will light up when OD is turned off. Lately driving around with OD turned on (light should not be lite) it flashes. Not consistently mainly when I am moving. Stopped at a light it tends to not flash. Any thoughts to why it is flashing. Transmission is shifting fine and goes in and out of OD fine. Transmission is controlled by factory computer as well as EFI.

 

[Bruners4]

I know that the pre OBD2 computers would flash the OD lockout light when there was a transmission code stored. Not sure about the newer ones yet. What year and model is the ECU from?

 

[Broncobowsher]

From your bio, looks like you are dealing with an '01 Explorer EFI.
Not sure the logic behind those. Did you match bulb type? Didn't replace an incandescent bulb with an LED for example? LEDs tend to light with only a hint of voltage

 

[duffymahoney]

This one looks sweet https://hgmelectronics.com/pages/fo...k8yzd-vA_GjNwTtvgdvioWOMmeWN1-T0tYX9-WmsRB3VI

 

[Steve83]

Either an intermittent short to ground on the TCIL wire (between the light & the PCM) or transmission faults detected by the PCM (read codes).

 

[Viperwolf1]

It has a trouble code for the transmission. You should probably put a scanner on it and see what it says.