My 2000 windstar has a flashing over drive light

First of all have an auto parts store check for trouble codes...The flashing overdrive light is a warning that the overdrive unit is overheating and/or low on fluid...#1 choice is overheating and you will be looking at a costly rebuild if this is not attended too soon...Have your radiator, which also has a transmission cooler flushed, cleaned and refilled immediately...Have someone check if fluid is leaking then cleaned and filled with fresh fluid...saailer

I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

have the transmission checked could be a shift solenoid

The flashing light means the overdrive will not work.
You could scan the computer and see if you have any trouble codes.
The codes will direct you as to what to test for the problem.

if the OD off light is flashing you may need either a TRS transmission range sensor or a VSS Vehical Speed Sensor.
Use a DTC reader to confirm

Hi Mamaberta7,
The OD light flashing is something you need to have checked using a scanner. Since this trans. was recently rebuilt,you want to get it checked soon. The transmission can default to full line pressure and this can cause damage. Also if the unit isn't locking up, it can cause the transmission to overheat.
The airbag light on and the horn not working are probably tied into the clock-spring. This is the most common concern with the symptom you have. Again,you can have the code pulled to confirm the problem or you can use a DVOM (Digital volt/ohm meter) and check for continuity through the clock-spring. If you want to check it yourself,let me know and I will get you the steps to down the system and the wiring diagram.
If you have any other questions,drop me a line. Thanks,Chuck

desconect the battery while 2 hours and connect it again and ready

The overdrive light blinking indicates a problem. Take it to a shop for servicing.

i recommend using a DTC reader to check the codes 1st but i suspect the transmission range sensor. it gives out due to a poorly placed master brake cylinder. the switch leaks and causes electrical problems with the TRS and other units connected in the wireing harness directly below the brake pressure switch.

od switch is on the shift lever. Should go off everytime you restart vehicle. Does it flash or is it on steady?

There isn't anything wrong with your car. This is perfectly normal. I have a 2000 ES300 as well as other people that I know and it operates in the same way. Overdrive doesn't mean the same thing for every car or transmission. In our case overdrive is simply a reference to the top gear which is 4th gear. When you switch overdrive off(which is depressing the button causing the O/D OFF dash light to illuminate,) the highest gear becomes 3rd because you turned 4th gear or overdrive off. The application scenario for this is usually mountainous terrain where a lot of uphill driving makes it more feasible not to up shift into 4th gear while ascending and descending. It will not switch back to overdrive or 4th gear until you re-engage it by turning the overdrive back on or repressing the button. Again, when the O/D OFF dash light is illuminated, overdrive which is 4th gear is off and the highest gear will then become 3rd. It will never shift into 4th gear while this light is illuminated or overdrive is off. When you press the button and the O/D OFF dash light is NOT illuminated overdrive is on and therefore it will shift into 4th gear as usual. This applies to all 97-2001 ES300's and probably any other car you drive tat exhibits this same type of change when overdrive is turned off.