OK just did the hoses on the 03.
The 02/03 years are easier than the later rigs. They have better access.
Step one get the new lines. If either line is leaking replace ALL of them. Return and pressure both. Make sure you get the correct lines. On the pressure side some have a pressure switch others don't, on the return side some have a cooler others don't. Look before you order.
To remove the bracket for the pressure lines, pull the grill, the LS headlight and the LS turn signal. Look through the hole in the rad support and you can see the two bolts. Reach in through the turn signal opening with a 10mm wrench to remove them (gearwrench or GM side terminal wrench is your friend)
Toss down a tray/pan to catch any fluid that you leak/spill.
Next remove the 18mm fitting from the rack. For easier access remove the electric fan and shroud, if you have heavy duty cooling pull the mechanical fan as well. Pop the serpentine belt off, possibly the oil filter as well to get more room as needed.
You have a couple options here. 18mm flare nut wrench, 18mm crows foot flare nut wrench or you can simply slice the old crimp sleeve in a couple spots, pry it off and pull the hose off the line, then slide a box end 18 down onto the fitting. (you can also bend the line to crimp it, then cut above the bend to get the wrench on BUT don't just cut the steel line, the steel filings can go directly into the rack. Not Good)
OK you have the 18 off, get the 16 mm under the pump next. Now if you don't have a 16mm wrench don't panic, usually you can use a 5/8" wrench on most 16 mm items. If you have the pressure switch on this line disconnect the wire first. Then break the fitting loose. Fish it out the line and remove the pressure switch. Install it on the new line. I usually do the return lines before I reinstall the pressure lines because you have more room. If you're not then install the new line.
Now remove the return lines, these are easier because they are low pressure. If you have a cooler the easy way is to cut both lines, remove the bolts holding the cooler to the rad support and pull the cooler and lines out. Now attach the new lines to the cooler and fish the lines back through the support and into the engine bay. Remove the line with the fitting from the rack and install the new line (make sure you have the o-ring in place) remove the clamped end from the reservoir and install the new one.
Install the pressure line and clean up the fluid. Reinstall the pieces removed to get to all the various bolts and fittings. Now to bleed the system. Fill the reservoir up, leave the cap loose, start the engine and turn the wheel back/forth a few times. Top off the fluid, repeat with the wheel until the fluid stops dropping. Take it for a drive and get it up to temp. Check the fluid level. Add if needed. Enjoy the lack of leaks.
I read a few posts where people couldn't tell for sure which line is leaking. Quick way to find out. With the engine off, wipe up the leaking fluid and get things as dry as possible. Now start the engine and look at the fittings. The return lines usually leak there. No leaks? Probably the pressure line. To test that turn the wheel to either side until it hit's the stop. Now look again BUT DO NOT STICK YOUR HANDS OR FACE DOWN CLOSER "TO GET A BETTER LOOK" THE LEAK WILL BE UNDER HIGH PRESSURE, HIGH ENOUGH TO INJECT FLUID INTO THE SKIN!!!
In the case of the 03 it didn't leak setting or under idle. When the wheel was turned to the stop it looked like a fountain!! The pressure line had degraded and had at least 4 pressure leaks. Even then it only lost about 1/2 pint of fluid over 2 weeks.
