2005 Coupe.

I am getting parasitic draw of 240-250ma. The car had been sitting for 4 days with the doors closed and the negative terminal disconnected when I did the test. Only thing open was the hood, which has no underhood light. My aftermarket head unit was coming on all the time, due to the switched wire being routed to an always hot fuse, but the head unit has been out for over a week now, and this test was done after it had been removed. The battery is not old, installed 2/2024 and I did take it to O'Reilly and it tested good. Also I tested the battery before it sat for 4 days, it was at 12.3V, and when I tested it again right before the draw test, it was still at 12.3V, so the battery is not discharging on it's own.

I used an amp hound to test every fuse in the car, and the locations I am getting draw are:

Passenger Compartment Fuse Box:

30ma at Fuse 18, which says it is for many systems....Interior Room Lamp, Illumination, Low Tire Pressure Warning System, Power Door Lock, Fuel Lid Opener, Remote Keyless Entry System, Trunk Lid Opener, Vehicle Security System, Power Window, Nissan Anti-Theft System, Rear Window Defogger, Power Seat, Headlamp, Daytime Light System, Turn Signal and Hazard Warning Lamp, Combination Switch, Parking Lamp, License Lamp, Tail Lamp, Warning Chime, Front Wiper and Washer, Rear Wiper and Washer, Telephone.

120ma at Fuse 19, also many systems....ESP/TCS/ABS Control System, Power Door Lock, Theft Warning System, Remote Keyless Entry System, Nissan Anti-Theft System, Rear Window Defogger, Air Conditioner, Turn Signal and Hazard Warning Lamp, Illumination, Triple Meter, Combination Meter, Warning Lamps, Warning Chime, Telephone.

20ma at Fuse 22....Fuel Lid Opener, Trunk Lid Opener.

And 10ma from Fuse 71, which is in the vertical block by the battery and says it's for Tail Lamp Relay (Parking Lamp, License Lamp, Tail Lamp, Illumination, Headlamp Aiming Control System)

Those don't get me to 240-250ma, only to 180ma. The other 60-70ma, I don't know how to find. Could it be relays?

Further, although I know where much of the draw is coming from, I do not know how to proceed from here to pin down the culprits, or how to rectify the problems.

Any insight on how to locate the remaining draw, and/or how to proceed with the ones I have found?

Thanks very much.

 

Have you checked fuses in the IPDM under the hood?

According to ChatGPT (take with grain of salt), the normal current draw is 20-50mA with the vehicle off and all computer modules asleep (Can take 30 minutes).

When you check for Parasitic drains, you need to keep the battery connected at all times and allow for all computer modules to go to sleep (vehicle locked). If you left the battery disconnected before testing, and then reconnected it prior to checking circuits, you're going to wake up all the computer modules and get false positive parasitic drain results. Same thing will happen if you disarm/arm the vehicle or open a door.

If you need to keep the doors open, then you will need to "trick" the car into thinking the doors are closed by pushing closed the door jam switches (and keeping them closed). Normally, the vehicle won't allow you to arm the security system if one of the doors/rear-hatch is open. If you can arm the security system, then your door switches are working as intended.

Most common sources of parasitic drains are glove blox lights staying on or trunk light. Check to make sure the lights are turning off when these items are closed. Also remove any 12V outlet accessories. The 350Z has two outlets, one under the passenger dash panel and one behind the center armrest compartment (could vary on depending on year). Another common 350Z source of drains and other problems is the brake pedal switch. The rubber stopper pads crack and fall out over time, making the car think the brake pedal is being pressed. This will quickly kill any battery. Simple solution, install a replacement stopper.

Cheers!
-Icer

 

Ah. I didn't think about waiting after reconnecting the battery. I will do that and try again and see if I get a different reading. Do I actually need to lock the doors or just fool the door switches? Also, almost every interior panel is removed, some of which have connectors (door cards, lower dash panels, etc) The draw was the same when all those panels were in and connected.

I checked all fuses in the IPDM and also pulled each relay and the only fuse pulling current there was #71, 10ma. That fuse says it's for the Tail Lamp Relay (Parking Lamp, License Lamp, Tail Lamp, Illumination, Headlamp Aiming Control System) I did clamp the door switches. I know the trunk light does go out. I don't believe the glove box light is working, I'll replace the bulb and see if that makes any difference. No 12V Outlet accessories were connected. (The fuse for them is hot all the time for some reason, but it's not drawing any current when the key is off) The brake stopper pad is intact.

I know the entire drain is coming from items run through the BCM. It has three connectors going in, big white, small white, and black. I disconnected the big white and the .25 dropped to about .14 and then disconnected the black one and it dropped to zero. I know it's possible to test each pin for draw by using multimeter probes on the pin and corresponding receptacle, and I started to try that, but the pins are so close together, especially on the white connector, that I was afraid I may touch two pins or the wrong ones. It's just too hard to keep a steady hand while contorted under the dash.

I don't know if this would be a cause, but I cannot find the hood switch, which is supposed to be near the wiper fluid reservoir. I am guessing it's gone and the connector for it is hidden somewhere, but I cannot find it.

Also, when I turn the key to "on" or "acc" there is a very low buzzing noise under the hood. Kind of sounds like an "open door buzzer" but very faint. It sounds like it's coming from somewhere around the throttle body area.

Thanks again for the info, I'll retest again with battery having been left connected and see if the number is reduced.

 

If there is a hood switch, then it's most likely part of the hood latch mechanism. I've never seen the switch near the wiper fluid tank, even though it's described as being there in the FSM. To my knowledge though, North American market Zs don't have a hood switch. I've never seen a "door ajar" indicator lamp set in the cluster when the hood is popped open.

The buzzing you hear with the key in the pre-start position is normal. I'm pretty sure this is the electronic throttle body servo/controller.

I don't think you need to activate the alarm for the computer modules to go to sleep. Simply shutting off the car and having all the doors/rear-hatch closed (or tricked closed) and then waiting 15-30 minutes should be enough. To know for sure, have your amp hound setup on the main battery terminal when you start the "go to sleep" process. Take notes at the start, then at 15 minutes, and again at 30 minutes. After 30 minutes, you should see the lowest reading (20-50mA). If you don't then you for sure have a parasitic drain somewhere. On rare occasions it could be a computer module that's not going to sleep. Since your BCM wiring has been messed with, I'm guessing that module is not going into sleep/standby/power-save mode.

The bellcap spliced wires on the BCM harness still has me concerned. Which two wires are spliced there? (See photo)

What wires are going into this crimped bellcap?


Cheers!
-Icer

 

Hey Icer, Thanks again for the info. The bellcap did not have two wires spliced into it together. It was just the end of one wire. The loose wire that was just hanging there was the other end of it as shown in the photo. I determined that the wire was for the little LED on top of the dash for the alarm system. (You gave me the first breadcrumb for the wiring diagrams which enabled me to figure out what the wire was for over in my thread about the head unit.) Connected them back together and the LED works fine now. So I think that wire has been put to bed and is not the problem.

I don't know what all the wire taps are for. There are a couple others in other places, including one on the OBD connector. I thought about prying them all off but I have inspected them and none seem to be poorly applied where they would be causing a short, so I hesitate to start prying and possibly damage a wire in the process.

Also the missing fuse for the start signal has been replaced and the wrong sized tall 15a one has also been replaced with a proper low profile mini.

 

OK, left the battery connected overnight with a charger on it and door switches clamped. Tested at 12.3 V this morning. Had to disconnect the negative to attach multimeter, of course. 250ma draw for 15-30 minutes, then it dropped to 200ma. I left the meter connected for several hours and it stayed at 200ma. Still getting exact same draws from the 4 fuses mentioned above using the amp hound, adding up to 180ma, assuming the "missing" 20ma may just be the amp hound rounding down.

Not sure how to proceed from here. My electrical testing knowledge and tools are pretty limited. Is there any tool that can be used to test each wire in the two connectors individually to narrow down the culprits further? Would a clamp-type multimeter that tests for DC current work? (Assuming there's enough room to get the clamp around each wire coming out of the connectors)

Maybe this?

 

I think you're overcomplicating it a bit. What I would do in this scenario is focus on the biggest offending circuit. In this case, FUSE 19. Start disconnecting modules that are part of this circuit while keeping the amp hound in place at the main battery. Trying to test individual wires under the dash or at the BCM will take longer and has some risk of causing a short.

1) AC control module
2) Combo meter module (white box under the AC controls)
3) ABS module
...and so on.

Check the amp hound after removing each module from the equation, if the draw suddenly drops, then you know where to focus.

If you had a thermal camera, that could help identify the source of the parasitic drain. Anything pulling current is going to get warm, unfortunately, decent thermal cameras are quite expensive.
Good Luck!
-Icer

 

That is good advice on disconnecting modules and I will do so. The amp hound doesn't work at the main battery, but of course, I can just use my multimeter. I looks like I could pick up a decent thermal camera for $150-$200. That's about the cost of one hour of diagnostics at any shop these days, so it would make sense to just spend a few bucks and have a tool I'll certainly use again sometime. Maybe I'll get one as a belated Father's Day gift. So, would I point it at the end connectors or the wires in between or just best place to have access?

Thanks again, Icer! Will keep digging and report back.

 

That is good advice, and I will try unplugging modules as suggested. The amp hound doesn't work at the main battery, it's just for testing draw on fuses, but my multimeter will work. I went ahead and picked up a thermal camera from Amazon that had over 400 ratings and 4/1/2 stars for about $150. One hour of diagnostic at a shop costs $150-$200 so it's worth the spend. I'm calling it a belated Father's Day present. Would you say I should point it at the end connectors, the wires in between, or wherever is the best access?

Thanks again, always appreciate the help.

 

There’s some good YT vids on how to diagnose parasitic draws with a thermal camera. But here’s the process in a nutshell…

1) Works best with vehicle in a garage, cooled off (heat from sun will make it harder to get accurate readings). Also helps to have left the car “asleep” or inactive for a while so only the offending modules or components are glowing (drawing current).
2) Simply point the camera over various computer modules, fuses, and relays. Anything glowing red/orange is drawing power.

I would refrain from focusing directly on the wire harness. I don’t think you will get accurate results. Thermal cameras are great, but their resolution isn’t that accurate because of how thermal dynamics behave. One hot wire will cause heat soak over time on the surrounding wires in the bundle.

But who knows, maybe you can isolate it down to a single wire. Awesome gift to yourself! Hope it helps pinpoint the problem!
-Icer

 

Ok, the thermal camera didn't pick up anything new. The only thing it showed is that the BCM is warm, which was already known. However, quite by accident, I believe I discovered one of the sources. While I had the door switches out and clamps on them, the driver's door closed from a little breeze and bent the screw tab on the door switch a little bit. While fiddling with the tab, I discovered the switch was not working right, the little push pin is frozen and does not move freely. I was able to move it in just a touch, and now my draw is down to 90-100ma. New switch on the way. Almost got this whupped.

 

Does this yellow connector below the hood latch go to a sensor or switch that tells the car the hood is open? Or is for something else? Two wires go to it, one orange, the other I think is white.

 

All bright yellow harness plugs are part of the SRS system. That front sensor is a "impact/collision" sensor.
Glad you figured out the door switch issue! Progress is progress!
Cheers!
-Icer

 

Thanks for the info, Icer! I did study the wiring diagram but I wasn't sure what that thing was. Tried a new passenger door switch just in case. That didn't change anything.

Question.....The little bulb in the glovebox behind the passenger seat. It was burned out and I replaced it with a little LED today. Does it just stay on all the time when the headlights are on or is it supposed to turn off when the glove box door is closed? And if so, is there a delayed turn off or does it just go off? I put my phone in there on video for over a minute after closing the door and it didn't go out. I know sometimes LEDs are polarity sensitive. Could that cause it to stay on all the time?

 

I always assumed the light turns off when the glovebox is closed, but to be honest, I've never tested the mechanism to find out. It might be triggered by the headlight switch or when the vehicle is locked. For example, the map lights near the rear view mirror will turn off (even if left on) when you lock the car.

I don't recall if there's an electrical switch around the glovebox latch, I had mine taken apart a few years ago when replacing the fuel pump assembly and doing the "hard to fill fuel tank" TSB. I only remember one electrical connection for the glove box which was for the light. Nissan did have slightly different versions of the glovebox depending on the year.

Now you have me curious. I'll test this with my phone to see the behavior.
Cheers!
-Icer

 

Thanks, I'll be curious to see what yours does.

 

Just tested. The glovebox light is part of the headlight/parking light column switch circuit.

So if headlights/parking lights are off, then the glovebox light should also be off.
Cheers!
-Icer

 

But if the headlights or parking lights are on, the glovebox light will also be on as well, even if the glovebox door is closed, correct? So it's just basically on all the time if the headlights or parking lights are on.

 

Yes, that is correct. These bulbs are very low wattage, so they won't make much of a difference. On the 06+ 350Zs, Nissan added some accent lighting in the door cup holders and center console cupholder behind the shifter. On my 06, these lights are all controlled by the headlight switch, same for the steering wheel control backlights, gauge cluster backlights, and AC control backlights. I think the only interior light that is independently controlled on it's own circuit is the trunk light (turns on when hatch is opened) and even then, the trunk light may shutoff when the vehicle is locked (assuming hatch electrical switch is broken, but mechanical latch is working) . I'm not 100% certain if this applies to all years, but on my 06, if I were to mistakenly leave one of the map lights or headlights on, exit the vehicle and lock it, after some time the car will shut them off.
Cheers!
-Icer

 

OK, Thanks for confirming. I am probably getting close to being done testing for now. I can live with 90-100ma for the time being. I have one fuse now pulling 30ma (#18) and one pulling 10ma (#71) and that's it. The rest is coming from elsewhere.

I disconnected the AC Amp, the triple gauge, the yaw sensor, a few others that were easy to get to and no change.

I also pulled all the relays (except the big ones for the cooling fans, as they didn't seem to just wiggle out like the others) and none of them affected the draw. I disconnected the fuel door connector and rear hatch connector and no change there, either. Same with the taillights. I may try unplugging the headlights and see if there's anything there, as they are aftermarket. And the fusible link FGHI under the hood.

The only other things I can think to try would be:

The yellow connectors going into the Airbag monitor at the back of where the center console sits. The steering wheel airbag is gone, obviously, with the ghetto removable steering wheel installed, and the seats don't have side airbags. Maybe something there.

This may not be related to the draw, but I also wonder if my OBD port is wired correctly. The below diagram is from the manual for my scanner. My OBD connector has 5 wires on one row and 2 on the other and the blanks don't match up to what the diagram shows here. Is the 2005 Coupe OBDII or is it some other protocol? My scanner isn't fancy, just basic, but I don't have any codes.

Definitely getting down to the little bitty odds & ends here.

Thanks again for the help & responses.