interior fuse box

My 99 ford 7.3 Diesel has a remote starter for starters. The #30 fuse controls a few things - fuel heater,wastegate,pcm relay and the "wait to start lite" stops working but here is the dilema when the truck is warm like 50 F degree's the truck will start fine but when its cold like this morning at 25 F the truck will blow the fuse. So when I bring it in the garage to work on it I cant get it to repeat. I have tested the relays and even swapped them out that does not seem to be a problem. I was just wondering if you guys have ever had any problems like these before or which path I should start down next.

Thanks Scott