8 amp draw on my 99 runner, I am on my fourth bout of trying to track it down. I put the meter in line with the negative and I have pulled out every fuse and relay I can find. unplugged every plug I can find in the engine compartment, I unplugged all the black boxes in the tailgate I've been living with removing the negative cable after each use for a couple of years, I am out of ideas. I can't believe its been this much trouble trying to find a 8 amp draw??? I'm hoping someone else who has been thru this figured it out and can share

Disconnect the alternator and check. A bad diode in the alternator could be the issue. Also the starter wiring.

You need to let it go into sleep mode before you do the test. That takes a little while.

When I do it I let the rig sit an hour before I look at the amps.


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what is sleep mode? and is that after it runs or after electrical power is shut off?

Sleep mode is when the ecu go to sleep and it takes a while. Not instant with every shut off. At least 15 minutes. I am not sure the time frame on a 3rd gen

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If not alt. Keep an Amp meter on it for at least 30 min to an hour. Should be Milliamps. If all is well..

Then slowly and methodically start pulling fuses one at a time and watch your Amp draw. When you find the affected circuits. The current will drop.

I am suspecting any of the circuits that are in the door jams.

For example:
Stop light circuit
Power windows
Power locks
Power mirror
Rear wiper
Rear power window...


Lots of times the wire breaks or insulation on the wires Crack in the door and tailgate boots will short etc
With the drivers door and the tailgate boot being the most properly.

This is extremely common in vehicles of the 3rd gen age.

Hope this helps.


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Anything below .040a after it goes to sleep is good. Above it is premature battery death.

My 97 was around .023a and my battery was at 12.2vdc every morning. It (the battery) was toast.


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You can check the current drop across any fuse as well. It should not be even a 1 mA if current is not flowing.

You mean with the fuse out check the socket with an Amp meter? Because you can't check for current flow unless you open the circuit and become part of it. [ well with a inductive Amp meter you can but you have to isolate the wire as it measures the magnetic field]

You can check for Voltage across a fuse as well as connectivity. But as I far as I know, you can't check amperage.

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If current is flowing through the circuit, you should be able to see it...

Whether you measure volts or amps would just depend on how you setup the meter.

A circuit can have voltage without using any amperage. For example, the controlled power side of a relay will have voltage but will not have any amperage usage if the relay is open.

Problem solved. the high draw off the battery turned out to be the Anti lock brake system. we could not get the fuse out for testing (its a big square thing with the fuse link visible thru a plastic window). ultimately the fuse had to be destroyed to get it out or at least break the electrical contact. no more draw the idiot light is on now but the brakes work fine other than no anti lock. I think a new fuse box would have to be installed because of what it took to rip it out. I opted for no antilock brakes. cars went without them for decades so I'm just going to leave it. I can only speculate what malfunctioned to cause it. with 300k on the clock I'm not gonna fix it. its only used for off road trips now anyway.

The very large fuses. [ABS] [ALT ] are bolted into the fuse box. You have to remove the bolts on the bottom of the fuse to remove them.

That can be a time consuming task.



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