Key On Wire

[Kable]

Its getting late and i just pulled the truck in. I need to find a key on wire. Seeing which wire everyone is using on the 1990s. Mines a 1990. I know i can find one but my heater isnt on tonight

 

[Kable]

I read yellow on the12volt.com but couldnt find it under my dash of my 1990, not saying its not there but i used a white wire since its only a signal wire.