Have issues with the door locks

[nauju]

I swapped a dashboard harness from a 1998 Chevy c1500 extended cab onto my 1998 gmc Sierra regular cab, everything went fine except now there’s an issue with the locks, when I push the switch it’ll unlock only it won’t lock, and when I push the button the interior lights dim a lot, is there a difference in the harnesses?

 

[AK49BWL]

Shouldn't be that much of a difference, I'd go back over everything you did and make sure you don't have something shorting out somewhere. The lights dimming significantly point toward that.