Yerg

So I bought my boy a GC with a 4.0 for his first vehicle. He loves it because it's a 4x4, its his, and mostly because he didn't have to buy it. I have discovered It has the battery drai and does not have any aftermarket stereo. I did a parasitic draw and found fuse # 7 under the dash is the culprit, drawing 1.1 amps if I remember right and 0.01 to 0.02 amps once the fuse is pulled. On the fuse cover it says the fuse is for skm/hood LP. I would assume hood lamp but there is no wiring or bulb under the hood for the lamp. Internet says license plate light. Anyone have any idea what is correct or have a wiring diagram? I've heard everything from door switch to body control module but at this point it could be the aliens flying spaceships over it at night..lol. I'd say I'm about to pull my hair out but being a Ford f150 owner it's already gone..any help is appreciated

dave1123

Okay, according to the wiring diagrams for my 2000, fuse 7 powers the Security Key Immobilizer Module, the Body Control Module, the automatic headlight sensor, the auto zone control module for the heater, AND the underhood light. I would suspect something is not allowing the BCM to go to sleep. In order for this to happen, all the lights need to be out including the interior lights, all the doors closed, key NOT in the ignition, and then it needs sufficient time to time-out, probably around 30 minutes. You can monitor this draw from fuse 15 under the hood in order to keep all the doors closed. Check the voltage drop across the 2 test points on the fuse itself. If no current is flowing in the circuit, the voltage drop should be zero.

If one of the door latch switches wasn't working, the interior lights would stay on, until THEY timed out, usually around 5 minutes, but the BCM would still be active. The best clue about the door switches is the interior lights would stay on while you were driving it. Hell at night!

97grand4.0

Dave is 100% right on the methodology here. I would add one further note that proved to be the source of my problems, albeit I have a 97 but these jeep problems seem to have common themes.
So on mine, the bcm was not going to sleep, did all the above, in frustration called a dealer and got a hold of a good tech, who said no, not so many problems with the door switches, although that will do it, including the hatch and rear window switch, but we have had a lot or problems with the key switch on the front door locks going bad.
This will make the bcm think the key is unlocking the door if it fails in that position. Junkyard for a new switch or two and after months of plodding, sure enough, watched the bcm go all the way to sleep on my digital voltmeter...1 amp is like where mine was hanging up, it did go there, and after a few more moments POP right down to 14 mV or so. Success at long last.