'94 Suburban Cig lighter fuse ?????

The cigarette lighter fuse (which I found out is the same fuse as the back door auto lock) keeps blowing.... any thoughts as to why??? Is this common? What does one do about this aside from changing the fuse often...
Thanks for your help in advance

hey there bkabe,
           have you check to see if there is a penny in any of your cig. light plugs,this happens alot and tends to blow the fuse over and over with out anybody kno why,buy go and check and see if thats it.
                                                 flawdafred

Thanks will have a look!