I am having the same issue with my park lights on my 93 JGC. It definatley has something to do with the alarm/security system. Door ajar switches not giving correct message to alarm system or something along those lines.
Short
there is no reason to pull the head to get at the oil pump.
The 2012 Jeep Grand-Cherokee has 39.9 in. of front head room.
The 2010 Jeep Grand-Cherokee has 39.3 in. of rear head room.
The 2004 Jeep Grand-Cherokee has 39.7 in. of front head room.
The 2013 Jeep Grand-Cherokee has 39.9 in. of front head room.
The 2003 Jeep Grand-Cherokee has 39.3 in. of rear head room.
The 2006 Jeep Grand-Cherokee has 39.3 in. of rear head room.
The 2002 Jeep Grand-Cherokee has 39.5 in. of front head room.
The 2008 Jeep Grand-Cherokee has 39.3 in. of rear head room.
The 2012 Jeep Grand-Cherokee has 39.2 in. of rear head room.
The 2001 Jeep Grand-Cherokee has 39.5 in. of rear head room.