Hi all,

So I've been trying to figure out this current draw issue for the last week and cannot for the life of me find the source. I came out one day after letting the Z set for a few weeks and couldn't start her.

Busted out the battery charger, and charged all the way. Started great and drove around that day. Car sat for no more than 2 days, came out and no start again.

This time I took out the multi-meter and put it in series and in DC current read mode. Checked between the negative terminal and it said I was drawing around 3 Amps... Started pulling fuses from under the drivers foot well.. nothing still 3 Amps... Pulled fuses from the other location behind the battery... still 3 Amps...

Figure it wouldn't hurt to start manually pulling things so I tried:
- Disconnect the harness inside the drivers door panel to the window motor/lock.
- Disconnect the harness inside the passenger door panel to the window motor/lock.
- Disconnect the tail lights
- Pulled the trunk light
- Pulled the dome lights
- Disconnected the stereo harness
- Ensured all doors were closed when doing tests

Then I got the bright idea it must be the alternator. Disconnected the fat wire going to the positive terminal block. Still 3 Amps...

Next I disconnected the grey and brown connectors from the positive terminal block so it was nothing. Obviously no amp draw... connected my Amp line.. BOOM 3 AMP DRAW... This is where things get tricky... disconnected amp wire, connected Grey connector to block.. 3 Amp Draw... wtf?? Disconnected Grey and connected Brown connector to terminal.. 3 Amp draw... WTF again..

At this point, anything connected to the positive terminal block, be it my Amp line, Grey connector or Brown connector, individually will cause a 3 Amp draw..

So what could be going on here?? In the picture below you can see my amp line, the top terminal connector which I assume is the alternator/starter line, grey connector, and brown. If any of those are connected without nothing else on the terminal block I see a 3 Amp draw...

Would a bad battery cause this? It is about 4~5 years old from Costco.

 

before you stress yourself much further i would go get the battery load tested. Just make sure the battery has at least 12.43 volts of charge for the test. When searching for parrasitic loads you also have to accout for the cars intelligent lighting system and security system. Some systems don't fully power down right away. Although different from the mustangs, their GEM module can stay powered 10-15 minutes after the car is switch off and the doors are closed. Issues with the GEM not powering down on mustangs were due to faulty door jam switches.
With the age of the battery i would suspect it first. One hard power down more then likely made the final straw but better to rule it out before you search further.
Good luck.

 

Thanks for the reply. I'll get a new battery today and after installation will wait 30 minutes with all the doors shut before doing another current draw test.

I don't think it can be the door jam switch as with the car on I don't see the open door indicator lights on the dash.

 

OK, so I got this resolved. Turns out I have a bad multi-meter, Craftsman brand. Anything that makes continuity with available current will cause this meter to pull 3~4 Amps.

Went to Harbor Freight, bought a $3 cheapo meter that did DC current. Low and behold, it read 0.00 A. With the dome light on 0.3 A. Verified it with a few other lights in the car and yep. 0 amps.. I can't believe I spent all that time when it was a bad meter the whole time.

I did buy a new battery from Costco as it seems my old battery was on the outs. Wasn't holding a charge long enough which contributed to me thinking there was a parasitic drain.

Thanks for the help rustyschopshop

 

lol that sucks. But at least you found the source of the problem.

 

For what it's worth, your old battery was a bit on the dirty side. Sometimes a dirty battery will conduct enough to cause a parasitic drain. Baking soda and distilled water will usually get rid of that problem. When I'm dealing with parasitic draws, that's generally where I start.

Glad you got it figured out though. Thanks for following-through on your post with the solution.

It's too bad not everyone builds a multi-meter like Fluke.

 

Glad you resolved the issue



Yeah i love my Fluke, have had it near 16 years now still works flawless.