FliesLikeABrick

Hi all,
6th gen, 2000 Civic VP.
The short version: I would be incredibly grateful if someone was willing to pull their IG1 fuse (40A screw-in fuse, in the box under the hood) with the car off and cold, and measure the current through IG1's connection points. Bonus points if it's closer to 2000 than 1996, and if it's closer to a CX/DX/VP trim level - just to minimize variables in parasite current.


The long version: I am investigating why our civic can't sit for as long as it used to before the battery is dead. Not just unable to crank to start, but completely flat, no lights/indicators dead. We already replaced the battery, just thinking that it was old (which was reasonable), but still there seems to be faster drop than expected.
Being an older car, its parasitic draw is low - about 40-45ma. But 95% of that is coming via IG1. From looking at some wiring diagrams, it seems like there should be nothing active on IG1 when the key is in the "off/lock" position.
So, I'm looking for a couple of other peoples' datapoints to confirm whether there is a 35-40ma parasitic current on IG1 when the car is off/cold.

ezone

If the ignition switch is OFF that better be ZERO current. See the red print below.

C&P from another recent thread:
If you study a wiring diagram for power distribution that shows all the circuits that originate at the 40A IG1 fuse and follow that though the ignition switch, to all of the individual circuits and fuses that the ignition switch controls:

The 40A IG1 fuse provides power to the ignition switch.
The ignition switch controls 4 separate circuits.
The 4 circuits of the ignition switch provide power to about 16 other fuses.

If the switch isn't turning off all 4 circuits correctly then you would probably find the group of fuses associated with a particular ignition switch branch remain powered up even though the key is turned off. (maybe a glob of solder melted off the back of the switch is bridging two wire connection points)

Since the 40A IG1 fuse supplies power to only the ignition switch, maybe inspect the harness from the switch to the dashboard fusebox (the spots many "installers" like to hack wiring)......and if you find nothing has been spliced into the harness then unplug the ignition switch harness from the fusebox and see if the draw disappears.

If draw is still present after disconnecting the ignition switch harness from the fuse box, you've got some searching to do between the engine compartment fusebox and the dash fusebox.





Industry standard for total battery draw (car off, doors closed, etc. "dark current") is "50mA or less" with few exceptions, and those old cars usually run somewhere under 30mA when all is well Probably more like 20mA or less.

Assuming the car is all stock, 99% of that measured draw should be through the "back up" fuse, used for ECM memory, radio memory, clock, stuff like that.

Does the car have aftermarket radio? Aftermarket alarm? Remote start? Lojack?
Buy-here-pay-here revenue assurance device installed? Anything that could have been wired into the power source wire for the ignition switch....


How long is the car sitting? Days? Weeks? Months?
If a battery is already in a low state of charge then it takes much less time to drain it than it would a fully charged battery.

FliesLikeABrick

ezone, thank you for the great, complete reply. It validates much of what I had understood from researching prior to posting.

Everything on this car is stock, electrically (and even mechanically, there were just a few silly things the previous owner had done trim-wise which I have since reversed).

Indeed, this is exactly what I was looking for clear confirmation on (albeit empirically, by having someone measure). I had reviewed the Power Distribution wiring diagrams and saw the same -- that there are zero downstream/branch circuits on the ignition's LOCK/OFF/0 position.

1-2.5 weeks. This car was demoted to "less-used-than-we-would-like second car" status last year, however in the past it has sat for longer without an issue.

I've been aware that this may be reasonable for a car to not be able to sit for a week or two without discharging, but it struck me as odd that:

• The car never had this issue in the past. Living in the city, even when it was our only car, it was subject to sitting for a week or two periodically
• We just put a new battery in, and it was *completely* flat after 10-14 days sitting
• The 40ma current on IG1 struck me as odd, for exactly the reasons that you and I have both mentioned

I'll still take anyone's measurement of IG1 in the LOCK(0) position on a 6th gen, but in the meantime I will begin testing the load on the circuits downstream of IG1's other positions.

ezone

Quick n dirty...... I'd unplug the ignition switch harness from the fusebox and recheck draw.
That would quickly eliminate a whole bunch of stuff.

Ever had water leaks? Windshield replacement?