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Ahh the harness killing interior lamps of the 928 from Hella.
yes this is why I suggest to keep the lamps turned off unless you absolutely need them.
putting in LED bulbs will greatly decrease the melting effect from an original bulb
I charged the battery then left it unconnected to test if it's really the battery. Nope, started right up after sitting overnight. Also a load test at AutoZone indicated the battery is OK.
Did the voltage test on all the fuses, but none indicated a current draw.
Alan--the God of all-things 928 electrical has addressed/answered this question many times before. He has singled out the door safety light. Can you pull this fuse and see what state the battery is in the next day?
to verify that the rear door lamps go out ,
put the window down,
then open the door look inside the door and look for the light to be on,
once you know where to look its easy to see if it goes out
Best thing i have done is wired a battery Tender connection to the jump post and a good ground. the connector is mounted on the inlet grill of the front bumper. It has become a habit just to plug in after each drive..never know when i will drive it again. Never fails to starts..cranks with authority.
Obviously, you need to find the cause of the drain first.
What I did was remove the ground strap and install a DVM in place of a ground strap. Set meter to read milliamps, might have not understood the exact scale / magnitude, but it worked and immediately showed draw.
I could see a significant draw and needed to eliminate it. .
Then I pulled and replaced each fuse, one by one.
No major changes, if any.
Then I pulled and replaced each relay, one by one.
BAM. Major electrical draw eliminated --- headlight relay, internally, had somehow failed and was pulling power, but not through the headlight fuses. I replaced the relay, solved.
I may have read the magnitude of the draw incorrectly, see the thread below, where Alan as not supportive of my conclusion, but that is based on perhaps a wrong scale reading I reported of the magnitude of the draw. Fact is the relay failed and replacing with a known good one solved the issue.
Re-installing the old relay caused the return of the problem. Infrared temp gage did not pick up the draw for some reason. Yes, I get all the logic about that amount of draw would result in plenty of detectable heat dissipation but I tried hard to read with my new infrared HF-supplied sensor and it didn't detect it. Just sayin. operator error I guess.
A piece of the puzzle that's sometimes forgotten is that some circuits may remain "alive" until power is completely removed. To measure those, the meter needs to be connected before the ground strap is lifted so the path for current flow is not interrupted as the ground strap is disconnected.
Alan--the God of all-things 928 electrical has addressed/answered this question many times before. He has singled out the door safety light. Can you pull this fuse and see what state the battery is in the next day?
One of first tests I did - it's not the door switch or interior lights.
Originally Posted by Landseer
Not all power draws run through fuses!
What I did was remove the ground strap and install a DVM in place of a ground strap. Set meter to read milliamps, might have not understood the exact scale / magnitude, but it worked and immediately showed draw.
I could see a significant draw and needed to eliminate it. .
Then I pulled and replaced each fuse, one by one.
No major changes, if any.
Then I pulled and replaced each relay, one by one.
BAM. Major electrical draw eliminated --- headlight relay, internally, had somehow failed and was pulling power, but not through the headlight fuses. I replaced the relay, solved.
A bad relay should be revealed using Stan's IR gun method - my tests were inconclusive. Will consider pulling relays if pulling fuses doesn't identify the source.
Originally Posted by dr bob
A piece of the puzzle that's sometimes forgotten is that some circuits may remain "alive" until power is completely removed. To measure those, the meter needs to be connected before the ground strap is lifted so the path for current flow is not interrupted as the ground strap is disconnected.
Charged the battery and disconnected for 2 days...went from 90 to 95%...good battery.
Connected car but left dedicated ground for compact sub disconnected...wondering if that's it...nope..car was 75% this morning.
A while back my windows started running really slow for no real reason. I pulled door panels off and lubricated everything really well and buttoned up but made really no difference.
I took my IR gun today and found out the relays were sitting between 54 - 56-7 degrees except the power window relay...it was sitting around 64 - 65or so...
For some inane reason I had another one...I think I thought one was bad and bought another to try...anyway put it in there...and first indicator I had that I had fixed it was when I pulled the hatch release...the motor spun much faster and I knew that was it....windows also running the way I remember them....
I had a situation where the battery was being sucked dry on my 86.5. It turns out the previous owner had tried to solve the issue by turning off all the interior lights (I did not know he had done this at the time ) what he failed to realize was the light that illuminates the door (when opened) was always on…but you could not see it, when the door was closed. Unless you looked into the slot that the window rolls down in, then you could see the light coming from inside the door. The issue was the relay that keeps the interior lights on for a few minutes after you close the door, was sticking on. I removed the relay and tapped it once and that did the trick.
When I do the current draw between the battery negative post and the ground strap I'm seeing a consistent 0.04 amps draw. Removing fuses and relays does not change that value.
Is that draw significant enough to kill a battery after 24 hours or so?
01-04-2017, 06:08 PM
) what he failed to realize was the light that illuminates the door (when opened) was always on…but you could not see it, when the door was closed. Unless you looked into the slot that the window rolls down in, then you could see the light coming from inside the door. The issue was the relay that keeps the interior lights on for a few minutes after you close the door, was sticking on. I removed the relay and tapped it once and that did the trick.