What would cause everything that is powered to stop working all of a sudden like the power windows power door locks power seat tail lights and radio on a 2003 Trailblazer LT

Ck the fuses here is the info if you already haven't.
1-Headlight washer jets
2-Turn signal flasher
3-Headlight washer, glove box light, engine bay light, instrument cluster
4-License plate lights
5-Instrument cluster, heated seats, auto trans display, outside air temp
6-Central locking system
7-ABS
8-empty
9-heated mirrors
10-empty
11-cruise control(auto trans)
12-on board diagnostic system
13-brake lights
14-interior lights
15-power windows, climate control
16-ABS, anti-slip(?)
17-heated door locks
18-right high beam
19-left high beam
20-right low beam
21-left low beam
22-tail and side marker (right)
23-tail and side marker (left)
24-wipers and washer jets
25-blower for heating/climate control
26-rear window defogger
27-empty
28-fuel pump
29-engine timing
30-sunroof
31-tail lights, cruise control, auto trans
32-engine timing
33-cig lighter
34-engine timing
35-trailer receptacle(?)
36-fog lights
37-radio
38-trunk light, central locking system
39-flashers
40-horn
41-empty
42-empty
43-heated seats

Ok there's the numbers. To figure out what the hell that means you have to look at the inside of the cover to the fuse box. left side of dash panel. Good luck.

Look under the hood fuse no. 12 should be for power windows. Or maybe something like a bad ground wire in drivers door harness.

a blown fuse could cause the power windows to stop working. take it to your hyundai repair shop if you are unable to find the blown fuse.

Check the Mega fuse, it is located at the front of the underhood fuse box.

Sounds to me like a switch problem The master window switch should be checked. Also check the door switches to see if they are getting voltage. Could also be bad window motors. Tests need to be done. Is there power to the power seat switch?

Sounds like body control module. Did water get inside the car recently?

that is the interior lights and alarm,remote module

Sounds like a possible BCM body controll module has shorted out partially. I think these are only at dealerships.

I just had the same issues. No headlights, interior lights, power door locks, radio controls on steering wheel, or dash lights. Pulled every fuse in cab and under hood, not a one was bad. I disconnected the battery terminals for a few minutes. When I reconnected them every thing was working.

It turned out that disconnecting the battery and reconnecting it reset the control module and fixed the problem.