Is it possible to run an ELD in a 97 FLD?

Yes

 

You can't just buy a new ecm and throw it in.

 

If it has an ECM, chances are you can run an ELD in it. If you're staying south of the border, you're not legally required to. Things are murkier if you plan on heading into Canada. There is some (unconfirmed) talk that the exception may be a little less generous on our side of the border (could be 95-96), once our ELD mandate kicks in.

Your best bet would be to contact various ELD providers and see if they have a hardware solution for you. You may be stuck with one of the more established players.

 

I have a 96 Series 60 in a 2015 glider. The company I lease to requires an ELD and it hooked up with no issues. I assume your rig will have the data port which is where mine was hooked up. They put a wyed pigtail behind the dash so the data port is still usable for engine diagnostics.

 

If its a mechanical motor then the answer would be no.
I would check to see if this company would even lease on a pre ELD truck, many will not.