jerybak

should i start a new thread?or continue with this one?

Alan

Maybe read what has been written and try that...

Alan

jerybak

perhaps I have missed something, I though I had done all the different steps/ ideas in this thread.

My signature has my model year 87' 928S4
I tested for a draw as directed with hatch wire pulled, and door pin pushed in
I then tested it again in the same manor after sitting fir a couple hours
My battery is AGM so I am not sure about the testing gravity fluid deal
The battery holds strong when disconnected from car(tested prior to finding the large draw)
Stated battery is only 2 months old
It seems I am still far from your stated 25mA, so I a wondering where to look now
Only item not factory is the radio
Rear defogger fuse is already removed as its never used
I have a new ground strap from 928RUS, however I cant get it to tighten properly(post are too small??)

This thread has helped me to determine that I do have a draw on the battery, to the tune of 1.2amps, then with the use of an IR gun as directed I located the circuit that was drawing the majority of current, it was the fuse 6 the AC, when I removed that fuse my draw dropped to 168mA. i pulled all other the fuses @ front CE Panel and the only one that created the drop was the AC, fuse Number 6.

It was stated to replace (3) relays first thing, one of the relays that was requested to be changed I have already replaced with a new one, which was relay "X". The other (2) requested I am unsure from the included description on this thread which ones to replace. I am not sure which other replays are from the description in replay number 29.....XVIII Cooling Air Flap? and IV Ignition Relay X????

I am new to this vehicle and trying to perform the requested work to the best of my ability, but I am just not sure which of the relays I should replace.... I also am wondering if 168mA is an acceptable draw on the battery or if I need to dig deeper yet also while chasing the AC draw I have already isolated.

Thanks again for all your help and understanding

Mrmerlin

OK lets go back to the #6 fuse,
put some deoxit 100 on it and plug it back in,
the reason its getting hot is because it has a bad connection,
use the IR gun to check the relays after the car sits for a half an hour see if any of the relays are warmer,
the X bus relay and the blower relay and the HVAC system relay could be sticking look at relays ,
IV= X bus
X= HVAC Blower
VIII =Defroster

zfhgh

Is this one quarter amp (.25A)? If so, is this excessive thus necessitating the search for a parasite?

Alan

Take the battery out take it to a good shop and have them load test it... a proper high current load tester is a large floor standing unit. If they only have a handheld unit - go elsewhere. You need to see if the battery capacity has been severely compromised. You can kill a battery in 2 months with too much abuse.

Do test the non-battery disconnect method as described. if you see a very different answer in this case then the debug is different, but at least you know the cause and how to monitor it. Do your interior lights work correctly in the door switched mode? One common cause of this issue.

You also need to do more detective work by removing the alternator from the circuit (bypass it - e.g. keep the B+ connections made). Damaged alternators can cause a constant leakage and this is unfused.

Also evaluate the other connections at the battery +ve post - these are typically also not fused - try removing them one by one.

Alan

jerybak

OK getting ready for a nice weekend of free time to get back at the troubleshooting, thanks again for all your support. A couple of questions/ responses before I dig in...

One of the first things I did after getting the car running was to replaced all fuses & 253b relays, after several aggressive deoxit sprays on the CE Panel. So i hope all these are good but i will review the (3) relays & fuse you spoke about with my IR Gun

I found a shop with a large free standing battery tester so that will get done this weekend also.

Please clarify what the "non-battery disconnect method as described" is, I have read this entire thread like 10 times so I wouldn't have to ask this question but I don't see what you are referring to.

My interior lights do work as they should with the door pins, however the red lights in the door jams do not work at all, have not gotten into trouble shooting those just yet, hoping its just the bulbs.

Please provide more detail on how to bypass the alternator.... "e.g. keep the B+ connections made"

I will also test/remove the 3-4 power wires at the battery + post as you suggested and look for a drop in the mA.

I found that when I move my test lead plug from "A" to "mA" it does not read anything and the interior lights don't work so I think perhaps my fluke may have a bad fuse????? I order a new Fluke 88-5/A kit so I should have that available for testing soon also, do you think my old meter has a bad fuse or something?

Alan

https://rennlist.com/forums/928-foru...l#post12829206

The alternator likely has 2 connections on the large B+ stud. You need to disconnect these from the alternator but they need to stay connected together, so find a nut & bolt and bolt them together seperately & insulate from the stud. The power runs from the battery to the starter, to the alternator, to the jump post and then to the CE panel. So if you don't connect these 2 B+ connections back together you will be missing almost everything else in the circuit.

You need to use a different connection for mA vs A on the meter. Look for A and mA labelling on the sockets. If you did use mA and it doesn't work you may need a new fuse - easy to replace, try radio shack.

Alan

dr bob

jerybak--

Re-read Alan's post #25 above. He details how to connect the meter before lifting the ground strap at the frame.

There are certail circuits in the car (interior lights, rear window defogger, and on some models power windows and sunroof) that stay active for a bit after the key is off. Following Alan's method tests for drains without letting those circuits 'drop out' from total loss of voltage as happens when you open the ground before testing for current flow.

[edit:] Looks like Alan and I were typing at te same time.

jerybak

Ok, yes I am sorry I should have clarified that on my post when I found the 1.2 amp draw I in fact utilized that method that Alan detailed, I then did it again and watched the meter for about an hour to ensure that no fans or anything were still somehow pulling on the battery. Only area I ran into an issue was when I tried to move to the mA plug on my meter as detailed in Alan's post, my meter wouldn't ready anything, so I guess a trip to the shack is also inline for this weekend, as my new meter won't arrive today....

dr bob

Most digital multimeters include a fuse in the current loop to protect the meter. With cheap meters, the third allegory of Fig Newton's Third Law of Electrical Reciprocity certainly applies: "When an expensive component is protected by a fuse, the circuit will invariably fail, protecting the fuse." Look for a fuse inside your meter. There are typically two-- one in the 100mA range and another at 10-15A. There's usually some guidance on the case, and for sure it's in the manual tha came with the meter.


In parallel with the current (sorry...) discussion on cheap bearings and tools, places like Harbor Freight carry throw-away priced DMM's typically on sale for $5 or less. I get coupon sheets from them regularly, with a 'free meter with ANY purchase' often included. For grins, I put one of them next to my expensive Fluke DMM. I was shocked (sorry again...) to find that they gave identical readings on voltage and current. The H-F unit doesn't have autoranging, doesn't measure frequency or duty cycle, does't offer current-loop source-and-sink used for industrial instrumentation, and has some amazingly junky test leads rated for 750 VAC (!!!). But for simple stuff on the car, the throw-away meter gets the job done. Just keep a fresh battery in it, since there's no warning that a weak battery will still give you apparently-accurate readings.

jerybak

Lol.... I know about them cheap tools but i live by many words of wisdom from my dad.
1. Buy a plunger before u need a plunger
2. Look people in the eye when you speak
3. Never lend something you can't live without
4. Nothing more attractive than a man in a fine tailored suit
5. Brush your teeth before you put your tie on
6. Buy high quality tools so you don't have to rebuy them

And a hundred more sayings!!!

dr bob

I completely agree withyour dad's philosophy. At the same time, I don't use fine bath towels as shop rags. The meter issue parallels that, especially if you are prone to mis-connecting things and letting some of the smoke out of said meter. As I sometimes unintentionally do.

jerybak

ok good days work today, started out with replacing the fuse in my DMM, got a new fuse and tested DMM, all good now, so I am using mA post on DMM for all testing. Started doing the battery disconnect draw test as Alan details, DMM reading the same 168mA, this was tested with fuse number no. 6 pulled as with it inplace I show 1.2A draw. Pulled the 2-3 small wires attached to battery pos+, DMM read dropped to 165mA. Put them back on as 3mA doesn't seem too bad of a draw.

Let the DMM read for about 45 minutes while I got some other stuff together. Grabbed IR Gun started in in fuses, all reading same temps no outliers, moved on to relays with IR Gun, and found a warm one, VI, pulled it DMM dropped to 98mA. As I started looking to find a suitable replacement for testing I noticed that when I replaced all the 253b type relays about 3 weeks ago I must have mixed up the VI & IV relays.

Put both VI & IV back where they should have been, started test over, 168mA was the reading. Pulled VI, dropped to 98mA, did a quick search on RL about VI relay saw a post from Alan about jumping it out by using 30/87 jumper, Installed jumper, started test again, DMM read 98mA. So it looks like my VI relay is bad.

On a freaking guess I reinstalled fuse no.6, DMM read 98mA, ok looked good..... reconnected neg battery strap, started car, whola HVAC is working, started the battery disconnect drain test again with VI jumper in place, and fuse no.6 in place, DMM read 98mA.

I like the windows working without the key, is the jumper ok to leave in place?
Why would AC Circuit/fuse no.6 show a draw when VI & IV are mixed up?
How do I bench test 928.615.126.00 Relay to verify its dead status?
Is 98mA an acceptable draw, or do I need to move onto the alternator bypass?
Would that relay mix up damage anything?

dr bob

Jerybak--

Some simple electrical math might help you decide how much loss is OK. You battery has a new advertized rating of something like 65 amp-hours. You really don't want to regularly draw it down more than 50%, and 25% may be a better number if you want to get years instead of months of total battery life before replacement. So with 0.1 amp draw, no more than ten days or so sitting there. Better if you keep it less than about 6 hours really.

Bottom line: Keep Looking for the drain.


Reminder that the ABS unit connects to battery positive directly. The power post for that is immediately in front of the power steering fluid reservoir. That wire running to it was bright red at one time. Best to lift ground at the battery before disconnecting the ABS feeder there. Tape it and tie it out of the way before reconnecting the ground and retesting your drain.