previa 1996 gs auto UK spec 95kmiles

[superhornet]

Hello

My Previa will not engage overdrive now. Reading through various forums I have done the following

1 check fuses

2 replace the thermostat

When pressing the overdrive button the od sign turns on and turns off when pressed again

My next task is to remove the green water temp sender. This was mentioned in another post I found on here which said it can be found on the top right front of the

engine. Where would this be exactly? is it somewhere under the bonnet? is it under the passenger seat access panel? or somewhere else under the car?

I'm hoping that this sensor is not working properly therefore the overdrive is seeing a low temperature so will not operate. If this is not the case, what else should

I look at before taking the car to a garage?

Thanks in advance.......