Hey there I have a 1996 Jeep grand Cherokee and it has a problem with the battery draining as many of them do. I just put a meter between the positive terminal and the battery and got a reading of .30, so I started to pull the fuses one by one in the fuse box under the hood and when I pull the red 50 amp fuse it drops to about .16 and then when I pull another orange 40 amp fuse it drops to zero or .1 . The owners manual does not have an accurate diagram of the fuse box under the hood it does not match up with mine so I do not know what these two fuses are for and or what is the next step now any advice? Thanks in advance it is much appreciated...

 

Welcome to CF!

The bottom of the cover has a fuse and relay diagram molded into it. I think the main fuse for the interior fuse box (or junction block) is a 50 amp. That's for anything that's hot all the time and a 40 amp for whatever is hot with ignition on. I could be wrong though. 0.3 amps isn't bad, but it WILL drain the battery in a couple of days. 0.014 is normal. Newer jeeps have an IOD fuse (ignition off draw) that is just for the memory circuits. They suggest you pull that fuse if the jeep will be parked for an extended period of time, like a week or more, to prevent draining the battery below starting levels. The problem with that is the PCM looses it's memory of your driving history and the radio's station presets.

 

Does you alarm work. When you lock it does it honk and alarm security light flash. I had the same issue with battery drain and security wasn't working. It would lock doors but not turn on security. Turns out it was the rear glass latch sensor. It fails and makes the jeep think that it's open so it prevents alarm from engaging and for some reason drains battery, it's really an easy fix if that's your problem. Remove lift gate cover and wiggle the sensor if it's lose simply push it back in and secure the end of it. I just clamped down on it with some pliers. You'll see what I mean when you get there.

 

Door sensors and stuff like that can keep the Body Control Module active and not go to sleep, which keeps draining power because it thinks you're coming back to drive it again. Normally if the doors haven't been opened in about 20 minutes, the whole system shuts down. Otherwise modules remain active.

This is where doing a parasitic draw test gets tricky. You have to wait for the system to completely shut down to find out the actual draw, but if you open a door, you're screwed until it shuts down AGAIN!

 

Agree w Dave 100% and usual suspects are the door lock switches on the front doors and also the rear glass or door. These stuck on or unlocked position will make the bcm not alarm the car and lights stay on, and or not go to sleep. Hot wired the back door switches, and replaced the door lock switches with junkyard ones and not a problem since on mine.