Viwing wiring diagrams to see what these thing's share , B+ voltage supply or maybe a control module ,such as a BCM - body control module etc..... It does sound like faulty wiring or maybe a loose connection . People on here can only give suggestions , ultimately it's going to take someone who is knowledgeable in automotive electrical trouble shooting to diagnose this problem . Do you know anything about automotive electical circuit's ? What a wiring diagram is an how to read one ? Electric Testing Techniques You Need to Know
Learn to diagnose electrical problem's an get a http://www.alldata.com/ service repair infomation manual an a DVOM - digital volt ohm meter . Also go http://www.autoshop101.com/ an study up on how electrical circuit's work .