Parasitic battery drain

Post Sun Oct 29, 2017 7:36 pm

I have a 155mA drain going on killing the battery in a day or so, pulling fuses and relays in fusebox under the hood one at a time didn't find anything other than when 21 is removed it drops 10mA from 155mA to 145mA a couple others cause about 1 or 2 mA which is nothing.

So there is an additional 140mA coming from somewhere? previously when i did it a year or so ago it was about 15mA

couple things of note is the lights that go on when door is opened dont work anymore and the passenger door wont unlock with the battery disconnected but there drivers door will.

i'm going to try unplug ABS relay and check out the lights and switch on the door when i get a chance

where else should i check?

Post Sun Oct 29, 2017 8:31 pm

Mine was caused by the alarm, removed alarm no more battery drain.

Post Sun Oct 29, 2017 8:58 pm

Connect the meter in series with the negative battery lead, and remove the smaller red leads from the positive battery terminal, one at a time, and see what happens to the drain.
One red is the feed to the fusebox and ignition switch, one is the feed to the engine ECU and DME relay, and the third, if you have it, is the feed to the ABS pump.
If the drain is still there with all these disconnected, then the alternator is at fault.

Post Sun Oct 29, 2017 9:21 pm

Ok thanks, car had a full re spray so could be a number of things disturbed or damaged

Post Mon Oct 30, 2017 9:54 am

at the hood terminal block on the firewall if i remove the feed to the fusebox alone it still drains, but if i remove the feed to the fusebox and what seems like any of the others from the terminal block as well then it stops.

from the battery in the trunk there is a thick black cable and a thinner black one in parallel with the thick they both run to the terminal block. what is the thin wire?

Post Mon Oct 30, 2017 10:19 am

i'm kind of thinking it is the ignition switch, when i connect the multimeter in series to measure the drain when i clip it on i hear a relay occasionally click, its not supposed to click unless the ignition is on

Post Mon Oct 30, 2017 12:36 pm

Best way is to trace the wires out point to point if you want to know what they do.

Post Mon Oct 30, 2017 12:39 pm

I used one of these to see what circuit was draining the most power then worked my way back along the loom/circuit.

Bought another one that I can attach to my Fluke Meter as its worth its weight in gold.

https://www.rapidonline.com/Sealey-TA12 ... -7EALw_wcB

Post Tue Oct 31, 2017 8:53 am

here is my terminal block/power distribution block

removing lead to fusebox doesnt solve the issue.
removing any other individual lead (those that can be) does not solve the issue

removing lead to fusebox and any other and drain falls back to normal. for example removing the wires to fusebox and pump simultaneously makes the drain stop but individually they dont. why would they be related?

the pump is an aftermarket vacuum pump that i have had installed for a few years, the wire goes to a separate relay and fuse that energises with ignition turned to in on position.

ive removed ABS relays, unplugged ignition switch, unplugged radio.

running out of likely sources, its 155-160mA only

Post Tue Oct 31, 2017 9:13 am

Boot light staying on?

Post Tue Oct 31, 2017 9:41 am

No it's disconnected for the moment. It's 500-600mA with it on

Post Tue Oct 31, 2017 9:51 am

What's the "pump" referred to in your pic, that seems to be connected to the smaller battery wire?
The smaller battery wire (which has a fusible link at the battery end) should supply the engine loom only. It's purpose is to isolate the engine electronics from some of the voltage drop and 'dirty' supply caused by the operation of the starter motor.
Also, you seem to have an extra wire - the one that goes through the bulkhead (or firewall, as you call it).

Post Tue Oct 31, 2017 10:23 am

It's a small aftermarket vacuum pump, I can move the connector to another position. It has been that way for some time before this issue but understand it's not correct.

So which one should be connected to the fusesble link one ?

I'm not sure where the other one goes once through firewall it's always been there

Post Fri Nov 03, 2017 8:07 am

found out the relay for pump was wired wrong i had the switched 12v and 12v battery switched at the relay socket so the ignition was powering the pump, luckily it only runs for a short period intermittently (it is also fused anyway). this wasn't the issue though.

heard some clicking coming from what sounds like the switch on door jamb that turns lights on and off as door is open and closed. ive also seem to have narrowed it down to 21 and 27 fuse combinations.