97 eclipse gst overdrive relay/sensor
 

I have a 97 eclipse GST. It's an automatic and the overdrive doesn't kick in. When I push the overdrive button, it doesn't engage and feels like it's in neutral. Someone told me it could be the relay or sensor. I would like to know if this is the problem.. If so, I need to know where the relay or sensor is located. Any help will be greatly appreciated.