Hazard lights wont work when in drive?

So in every car I've ever driven the hazards work regardless of what gear you're in. But I just bought a 1991 Ford ranger a couple months ago and realized the hazards will not work when in drive. I have to either be in park or neutral. When I'm in drive and turn them on they just stay lit up solid. As soon as I throw it in park they blink like they should. I haven't needed to use them in drive but it was something I noticed when I hit hazards on accident. Can anyone explain this? Is it something to do with the model or year? Never seen this before.

Read more: Hazard lights wont work when in drive?