Mystery Battery Drain
08-26-2023, 06:56 PM
#1
Track Day
Thread Starter
Join Date: May 2021
Location: Denver
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
Mystery Battery Drain
I have an 84S US manual, and I've discovered is has quite a substantial battery drain (with ignition off). ~2.7amps... I've checked (and actually removed) all the fuses, and any auxiliary lines to the battery, and the drain is still present. While the PO certainly had their way with some of the electrics, and the cooling fan was switched to electric (I've pulled out those fuses as well), I'm at a loss as what/where to go next.
Thoughts?
Thoughts?
08-26-2023, 08:24 PM
#2
Team Owner
remove the parcel tray and the CE cover boards,
get an IR gun.
go for a 10 min drive then park the car with the windows down
lean in and shoot the CE panel relays,
notice the warm ones.
go for a walk come back in 10 mins.
Make sure you keep the doors closed
shoot the CE panel again look for any warm relays.
pay attention to the X bus relay and the window relay.
look into the window slot in the doors to see if the rear lights are on.
NOTE this works better if you have previously made sure these lamps are working.
make sure the lamps are off.
Unplug the hatch latch connector a 2 brown wire connector at the hatch latch.
get an IR gun.
go for a 10 min drive then park the car with the windows down
lean in and shoot the CE panel relays,
notice the warm ones.
go for a walk come back in 10 mins.
Make sure you keep the doors closed
shoot the CE panel again look for any warm relays.
pay attention to the X bus relay and the window relay.
look into the window slot in the doors to see if the rear lights are on.
NOTE this works better if you have previously made sure these lamps are working.
make sure the lamps are off.
Unplug the hatch latch connector a 2 brown wire connector at the hatch latch.
The following users liked this post:
davek9 (08-27-2023)
08-26-2023, 08:56 PM
#3
Rennlist Member
Possibly the alternator has bad diodes or rectifier causing drain. This thread might be helpful. Even though you don't mention any abnormal light activity, the alternator could still be the cause. https://rennlist.com/forums/928-foru...ts-act-up.html
The following users liked this post:
davek9 (08-27-2023)
08-27-2023, 07:45 AM
#4
Rennlist Member
If you remove the two power cables from the altgrnator- carefully join them together temporarily and test for earth leakage and the problem disappears it is a pretty sure sign that the diodes have gone. Alternatively you can carry out a diode test if you have the means to do so.
08-27-2023, 12:46 PM
#5
Drifting
If you don't have an IR gun, remove all the relays and check for current drain.
If it's gone, add the relays back one-by-one checking the current draw each time.
If it's gone, add the relays back one-by-one checking the current draw each time.
08-28-2023, 08:27 AM
#7
Drifting
I would next remove all the smaller red wires from the positive battery post and check for current draw.
If gone, reconnect the wires one at a time and measure current draw.
If gone, reconnect the wires one at a time and measure current draw.