You have to use a scan tool, but first you have to find out what's wrong:
Bulletin No.: 05-09-41-001B
Date: June 02, 2008
Supplemental Inflatable Restraint (SIR) Light ON, Diagnostic Trouble
Codes (DTC) B0013, B0014, B0017, B0018, B0024, B0026, B0043, B0044
(Inspect and/or Replace IP Harness to Inflatable Restraint Module (Air
Bag) Yellow 4-Way Connector C221 and/or C222)
2003 - 2006 Cadillac Escalade Models
2003 - 2006 Chevrolet Avalanche, Suburban, Tahoe
2003 - 2007 Chevrolet Silverado (Classic Only)
2003 - 2006 GMC Yukon, Yukon XL, Yukon Denali, Yukon Denali XL
2003 - 2007 GMC Sierra (Classic Only)
This bulletin is being revised to add the 2007 model year for
pickups and change a part number. Please discard Corporate Bulletin
Number 05-09-41-001A (Section 09 - Restraints).
Some customers may comment that the Service Supplemental Inflatable
Restraint Light is on. Diagnosis with a scan tool may indicate a DTC
B0013, B0014, B0017, B0018, B0024, B0026, B0043, B0044.
The most likely cause of any one of the following DTCs: B0013,
B0014, B0017, B0018, B0024, B0026, B0043, B0044 is improper
connection/high resistance in the IP harness to inflatable restraint
module connector C221 and/or C222.
DTC B0013, B0014, B0017, B0018, B0024, B0026, B0043, B0044 will set when one of the following conditions occur:
||The SDM detects the air bag module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.
||The SDM detects that the voltage at the air bag module high control
is less than 2.4 volts and deployment loop resistance is 6 ohms or
greater for 500 milliseconds.
||For additional diagnostic information, refer to DTC B0013, B0014,
B0017, B0018, B0024, B0026, B0043, B0044 in the appropriate SI Document.