I’m a moderator for this topic and I wonder whether you’re still waiting for an answer. If you are, please let me know and I will do my best to find an Professional to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!
There is a large wire harness coming from behind the dash and going into the top of the fuse box preventing it from comming out. I had the box completely unbolted from the firewall, but could not remove it because of the large loom. A local Kenworth dealer mechanic told me that the loom had a connector that would dis-connect, but there is no connector. That is why I'm sure the fuse and relay sockets must come out from the front. It looks like the wire harness for the dash is assembled to the back of the front half of the fuse box, then the harness is fed through the firewall and then the back half of the fuse box is snapped or connected somehow to the front half and then bolted to the firewall. That is the best way I can describe it. What do you think?
Just to let you know, I figured it out. there are two lock tabs on the bottom of the front half of the fuse box that look like guides. One of the tabs on each side can be pushed sideways while inserting a hook pick behind the bottom relay socket and pulling forward and unlocking that side of the front half. Then do the same thing to the other side and the two halves of the fuse box seperate. It kind of came to me when I was describing it to you last night. Now you know.