O/d Off Light On Manual Transmission 98 Gt. Normal?

[BAM099]

Sorry for the vague title. I have a 1998 GT convertible manual transmission and I ran the VIN code on Ford's Fleet site to verify it was from the factory a manual, someone else said maybe it was converted. The O/D Off light is constantly on the dashboard but I thought that was an auto transmission issue. I was just wondering if anyone could think of why that light might be on. I searched but it brought up a bunch of topics relating to auto's so I'm sorry if it's been answered before. TIA for any help!

 

[phatboy5015]

Maybe the ECU has been swapped at some point?

 

[BAM099]

It seems so random that someone would swap the ECU like that but I suppose it could have been. Someone else had mentioned maybe a shorted wire somewhere. I just wanted to make sure that nothing was going to be hurt by the light being on. Thanks for all of your guys advice