Lots of Fenders, especially vintage-style, will have their truss rod adjustment and the heel end of the neck instead of down at the headstock. And, in lots of cases, this means you have to slacken off the strings, slacken off the neck screws and remove the neck to gain access to adjust the rod.
That's no fun. Sometimes, there's a slight hollow in the pickguard or body that might allow you to get at the adjustment without removing the neck (but often it's too shallow to be more than a token feature).
Some Telecasters, however have a channel cut between the neck pocket and the front pickup cavity. Because the neck pickup is often mounted direct to the body, removing the pickguard on those Teles is easy. And, if you're lucky, you'll have a little notched channel to get at the truss rod.
You'll need a right-angle/offset screwdriver to actually adjust the rod in this way. Right angle screwdrivers aren't hard to find but there's not a lot of room here so you'll need one with a fairly short business end. If you want to play it safe, for a few bucks, Stew Mac sells a Tele truss rod 'crank' that does the job nicely.
Can't remove the pickguard? No access channel? You're unscrewing the neck then. Sorry.
Oh, a last word. Some instruments have this access but use a hex/allen adjustment on the truss rod. Ball-end hex wrenches may let you adjust the rod at an angle over the pickup but be careful not to damage the pickup or the truss rod. Lowering the pickup may help but, if things seem precarious, just bite the bullet and remove the neck.