I have a 95 Grand Cherokee Laredo and have recently started blowing fuse 12 frequently. The onboard monitor show a taillight issue and I have found that there are quite a few items on this fuse. I have completely eliminated any issues from the rear lights forward to the splice connector located under the rear seats. I'm having problems tracing from there forward. I have a haynes manual which is an excercise in futility as far as schematics are concerned. I have eliminated the front parking lights (also the same circuit) but only at the lights themselves. I have checked their sockets and know that the issue lies from there backward. I currently have the dash torn down to black abs plastic with the instrument cluster removed and when I ohm the headlight switch dark blue w/ red tracer (its called L90 circuit in haynes) I'm getting 1.2 ohms (200 scale) from power to ground. At this point I'm at a standstill I know there is a splice somewhere under the dash called L90-2 that connects multiple items together (all parking lights, inst cluster lights, something in the transmission, License plate lights) but I am unable to find that splice and I'm out of ideas. The only Field Service manual I have been able to find for under $100 I'm still waiting for and its actually for a '94 (I'm 80% certain it'll be the same) But I am hoping someone here can say "hey stupid, you forgot to check xxxxxxx!"

 

Is there a trailer hitch and plug on your rig? And if so, is it a factory wired plug or an aftermarket plug?

 

Aftermarket, but has been eliminated. First thing I checked