Go ahead, laugh at me.  I started to change the oil in my wife's XJ at dusk yesterday 

.  I had to work pretty hard to get the oil drain plug off because the local shop I let change the oil last time had torqued it down hard 

.   The seal was toast and they replaced it with a metal washer without telling me.  So I cruise to the auto parts store to get a new one.  It was pretty dark when I swapped the oil filter, which was also torqued hard enough to pull the seal off.  I heard an unusual crunch when I put it on 

.  Yeah so today my wife told me she couldn't go to the store because her jeep had no oil pressure 

.  I had crushed the oil pressure switch putting the oil filter on  

.  Only work on your Jeep under bright lights 

!  And change your own oil.