No power to running lights on tow harness

I just bought a trailer and 7 into 4 adapter for the tow harness. I'm not getting juice to the running light connector. Turn signals, hazard and break lights work fine. I've checked the owners manual for a fuse but can't find one labeled "running lights" Found left stop/turn fuse, right stop/turn fuse, trailer brakes, and one just called trailer, but nothing called running lights. Is it grouped in with something else or am I looking in the wrong direction for a fix to my problem? :banghead:
Thanks,
John

Sorry, forgot to add it's a 2004 Trailblazer Ext LS

I had the same problem with my 02 TB LT. There are two fuse boxes, one under the hood and the other under the drivers side rear seat. Open the one under the rear seat. Once open, check the fuses, I am drawing a blank on the exact fuse name. This puzzled me for about two months, and then I deceided to take a look at the other fuse box, the under seat one. I replaced the fuse, and presto, all lights work. Hope this helps with your problem. ScarabEpic22

Do you recall if it was a regular fuse or one of the big black squares which I assume are relays?
I thought I checked all the fuses but I'll go over them again. Thanks for the response, I was begining to think nobody looked at these messages.
John