No check engine light.

[Fairlane6t9]

Hi all. I purchased a 94 Winnabego Brave a couple months back. It’s an F53 chassis with the 460 and E4OD transmission. It had a bad transmission. I’ve got a remanufactured unit installed. The check engine light does not come on when turning the key to the run position and never has since I purchased it. The bulb is good. The transmission seems to be in limp mode. I spent 20 years in the automotive parts industry but have very little experience with rv’s. Where do I start to sort out the check engine light?