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5 Posts
Discussion Starter · #1 ·
So I went to start my Jeep and it wasn't turning over. Grabbed my Multimeter and checked the Voltage on the Battery (11.6V)
Hooked up my battery charger and got it to 12.6V. Turned the Multimeter to Amps to check if there was anything pulling power while the jeep was off.
Turns out there is a 1.6Amp draw while the vehicle is off.
Started pulling fuses and I found

M12 - Amplifier (30Amp Fuse GRN) - Pulling roughly 1Amp
M13 - Cabin Compartment Node, Wireless Control Module, Siren, Multifunction Control Switch, Clock Module (20Amp YLW Fuse) - Roughly pulling .300 Amps

Still have roughly .200ish Amps being pulled

I don't know how many amps are supposed to be pulled with the vehicle (key off) but I've heard 50mA ish?
I don't know how to fix the issue if the problem lies within the Amplifier or Cabin Compartment Node

Any tips on what to do next (Not much of a mechanic/electrical tech kinda of guy)

This is for a Jeep Wrangler Unlimited '08 if that makes much of a difference

618 Posts
Did you measure between the pos battery cable (disconnected from the battery) and the battery post? Did you wait 20-30 minutes after disconnecting before measuring?

Step 1
Charge your battery if necessary. Dead batteries (and even weak ones) don't give accurate results on a draw test. The dome light is a good indicator of battery strength. If the light is weak, pulsating or refuses to turn on, you'll need to charge the battery.
Step 2
Shut off everything in the car. Pull the keys out of the ignition. Ensure all service lights are off, lighted compartments closed and doors shut. Open the hood, and disconnect the trouble light underneath if your vehicle has one. Wait for 30 minutes before moving on to Step 3. (This enables normal drain from interior components to finish cycling.)
Step 3
Set your battery tester to 10 amps DC. Disconnect your positive battery connection (red cable) and position it safely away from metal components. Connect the meter's positive probe to the battery's positive post while simultaneously holding the negative probe in the air; keep it away from anything metal.
Step 4
Place the negative probe on the end of the removed positive cable to complete the circuit. Yes, you're putting a negative on a positive. Yes, this is ok. If you have a severe drain, you're likely to pop a fuse or two-identifying your problem.
Step 5
Check the meter reading. A normal reading is usually under .035 amps. If you have a minor drain that causes a higher reading, you'll need to check each component.
Step 6
Remove the first fuse in the box, and check to see if the load problem is resolved. If not, replace the fuse and check the next one. Repeat the process with all fuses. If the fuses check out fine, you have a wiring problem.

Remove the tester and reconnect the battery. Follow the hot wire to the next connection. Remove the positive cable and connect the positive probe of the tester in its place. Connect the negative probe to a metal object. Check the meter. If the drain isn't resolved, reconnect as normal and follow the hot wire to the next connection. Repeat this step at each connection point until you narrow down the problem.

448 Posts
Last question answered first, 50 mA would be normal dark current, altough it seems to be higher with new vehicles.

How did you measure the current? The way I do it is to close all the doors, wait 5 minutes (the JK seems to play with the vents for a while after closing the last door). Then make a connection with the multimeter on the battery ground strap, then remove the battery ground strap. If you just put the multimeter across the battery to measure current the current surge will pop the fuse in the multimeter 99.9% of the time. Also consider for some vehicles they current with the doors locked is less than unlocked as some systems are powered down.

As for the draw, who knows. My amp powers down after about 30 seconds.
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