<h1>1999 GMC Sonoma – Remote Fob Programming Guide</h1> <p><font size="3"> This guide walks you through the manual process of programming keyless entry remote fobs for your 1999 GMC Sonoma. All remotes must be programmed at the same time during this session. If any remotes are skipped, they will no longer work after programming is complete. </font></p> <p><font size="3"><b>Step-by-Step Instructions</b> </font></p> <ul> <li><font size="3">Step 1: Secure the Vehicle Make sure all doors are completely closed. This prevents the system from failing to enter programming mode. </font></li> <li><font size="3">Step 2: Insert the Ignition Key Put your key into the ignition switch, but do not turn it yet. </font></li> <li><font size="3">Step 3: Press and Hold the Unlock Button Locate the power unlock button on the driver’s door panel. Press and hold this button firmly. Continue holding it until you are told to release it in Step 9. </font></li> <li><font size="3">Step 4: Prepare for Programming While continuing to hold the unlock button, complete the next four ignition steps in rapid succession: </font></li> <li><font size="3">Step 5: Turn the ignition key to the ON position (do not start the engine). </font></li> <li><font size="3">Step 6: Turn the key back to the OFF position. </font></li> <li><font size="3">Step 7: Turn it again to the ON position. </font></li> <li><font size="3">Step 8: Finally, turn it to the OFF position again. </font></li> <li><font size="3">Step 9: Activate Programming Mode Now, release the unlock button. If the procedure was successful, the door locks will automatically lock and unlock—this confirms the vehicle is now in programming mode. If the locks do not cycle, you will need to restart the entire process from Step 1. </font></li> <li><font size="3">Step 10: Program the First Remote Press and hold both the LOCK and UNLOCK buttons on the remote at the same time. Continue holding them for up to 30 seconds. Once the locks cycle again, the remote has been successfully recognized. </font></li> <li><font size="3">Step 11: Program Additional Remotes Repeat Step 10 for any other remotes you wish to program. Be sure to include any previously working remotes, as all remotes must be programmed in the same session.</font></li> <li><font size="3"> Step 12: Exit Programming Mode Turn the ignition key to the ON position to signal the end of programming. Then remove the key from the ignition. </font></li> <li><font size="3">Step 13: Final Check Test each remote to confirm that locking and unlocking functions are working as expected.</font></li> </ul>
