No tail lights on a 99 jeep grand Cherokee - Jeep Cars & Trucks

There are many running lamps. best name is park
some go front, some go tail, some go side, and some go
to dash. largest run of 1 circuit on car.... park.
then HL switch, 1 click, does dash glow.?
does all side lamps glow, and front and rear.?
check fuses first. as that is always first.
some jeeps have a relay called , PARK.
license plate rear lamp out too>????????????
fuse 6 in JB , junction fuse box is park
as is park relay
the BCM computer, sees you turn the park switch
the BCM the (the brain inside) energizes the PARK relay
and if the fuse is good , all parks glow.
including the lic, plate lamps.

what we do is check battery voltage first.
12.6vd is good, less is bad. i do this with parks on, and key on pocket as parks work all the time.
then check fuse 6
then last scan the PCM
if the PCM reports BCM errors, for park. we'd not IGNORE THAT.
did you?