More often then not its a dirty door ajar switch which is located in the latch in the door.
													
																	2006 f150 door ajar switch replacement. 
									
	
		
	
																	The door ajar switch is a plunger type of switch. 
																	Post by wujcik123 wed jan 12 2011 8 16 pm. 
																	My old door check strap was broken when i bought this ford f350. 
																	Let go in depth with some theory and testing of ford door ajar switches. 
															
													
									
	
		
	
																	A mix of rust penetrant and wd 40 fixes most of these. 
																	The sensor typically uses a switch with a spring loaded plunger that is compressed when the door is closed and is released when the door is open. 
																	If no one answers up do a search on door ajar switch or dome light switch there has been posting about spraying the door latch with wd40. 
																	Shoot a light lubricating oil into the latch and open and close the door several times to work the lube into the pin switch. 
															
													
									
	
		
	
																	If that doesn t work disconnect the electrical connector at the door latch and test for bcm power and ground. 
																	2006 ford f 150 lariat 5 4 triton. 
																	It made a terrible creaking noise whenever the door was closed so i had enough. 
																	Welcome back to the shop. 
															
													
									
	
		
	
																	This action opens and closes an electrical circuit sending a signal to your vehicle s computer activating the door ajar warning light when the door is open. 
																	My 2006 ford f150 driver side door sensor is not working. 
																	06 f150 door ajar light on. 
																	Number 6 is the door ajar switch number 2 is the door latch. 
															
													
									
	
		
	
																	Get yourself a can of brake cleaner with a straw and a can of wd 40 from a parts store and install the straw in the brake clean now spray the latch liberally then close and open the door six.