GMC Repair: 98 Tahoe Electrical issue (5.7 V-8), light fuse, factory radios

Question
Looking back, all of these things might or might not be related.  The first problem started three weeks ago when someone on the road told me my taillights were out (along with the dash lights) shortly after I got a car wash.  After replacing the parking light fuse the problem stopped so I chalked it up to something with the carwash and my trailer lights.

About a week later, the gas gage started vibrating (moving back and forth about 1/16 of an inch) but was keeping accurate amount in the tank and it did not matter if the truck was running or I just the key turned on.  After the truck sat over the weekend, Monday morning the battery was dead.  Charged the battery up and worked fine Mon thru Thursday until Friday morning when it was stone dead.  Battery checked poor when AAA came to help my wife so they jumped it.  We replaced it under 3 yr warranty Friday morning.  It ran fine on Friday and Sat.

It sat in the driveway from Sat afternoon until 8:30PM Sunday when I happened to try and put something in it.  The new battery is dead and has less than 2 volts on it.

Next, I went through the fuse block in the passenger compartment, pulled each fuse, and checked with an Amp meter.  The "Radio (Battery)" one (#19) showed 740 mA.  The "Security/STRG" one (#21) for the EVO/Passlock Module feed showed .04 mA but then went to 0.00.  All the rest do not show any draw.

Have you come across anything like this and do you have any idea where I should be looking for a short???


Answer
Hi
Has or did the fuel gauge still jump?
I think the radio is at fault.  I have run into the factory radios staying on internally and causing the battery run down. The 740ma draw is WAY to high and will run out a battery in no time at all. If the draw ceases after the fuse is pulled, I would really suspect the radio.
The radio also is fed by the Park Lmps fuse...so there may be your original problem. Keep your ampmeter hooked to fuse and unplug radio. If it goes away you found the problem, I Believe.
If the fuel gauge is still acting up, go to your local GM dealership and purchase a bottle of part Number  88861011 (for U.S. ACDelco®, use 88861013) (in Canada, 88861012) and add it to your fuel tank.
It MAY help clear up that problem.
I Hope this helps.
Good Luck
Pawl