Hi all,

I just got through testing my Bonneville for a parasitic drain on the battery because I've gone through 3 batteries in a fairly short period of time. I checked the current draw sitting idle and after 5 minutes with nothing open/powered on etc. it gets down to 120ma. My understanding is that it is not normal to have over 50ma draw. I have pulled all fuses one at a time (pull and then replace) with no change in the draw - both fuse boxes (under seat and under hood). I'm at wits end with this - just can't figure out what is drawing power.

I have a car starter installed in the car with the viper smart start module which is cellular so I suspected that first. After a couple of hours messing around I finally located the cellular part of the system and removed the fuse for it. Rechecked the drain and still at 120 ma. I also disconnected the wiring harnesses from the car starter and drain stayed the same.

I also have an aftermarket JVC stereo with some integration modules for chime and steering wheel controls. That is my next suspect just because it's aftermarket.

What I'm wondering is if anyone has a stock GXP that would be willing to test theirs and see what the "at rest" drain should be on the battery or if someone just happens to know for sure.

I pulled a few suspect relays while testing (ones that were warm) but my thought is that the relays are probably fused at some point or another so probably not necessary to pull?

Thanks
Rich

Most of these modules are not asleep after only five minutes. If I recall from the service manual, you need to wait at least 20 (perhaps 30) minutes. Even retained accessory power is active for 10 minutes. The VCIM will operate at a reduced power, but will not fully go to sleep for something like 48 hours. As I recall, somewhere around 50mA is the expected draw.

My first suspect is always aftermarket electronics, not that this is always the case. Anywhere you read through the service manual when diagnosing obscure problems, GM repeatedly says to disconnect any aftermarket electronics before continuing. So, I would be sure that you disconnect power to non-OEM equipment before moving on.

Is it safe to assume that you're correctly using a battery disconnect switch as part of the procedure? This is important to ensure modules don't wake-up again as soon as you start measuring current draw. Some of the things you've said certainly suggest you have some knowledge about using a meter and diagnostics, which is definitely helpful.

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No battery disconnect... I just hooked my DVM in line and I'm reading the amp draw. I have a 10A meter. Problem is every time either it disconnects or I disconnect it everything resets. As far as the aftermarket electronics that is what I was targeting first. The stereo is a pita to get in/out of the dash so I can't get behind it easliy but pulling the radio fuse did nothing. I would probably need to pull the radio and accessory fuses both because I think the integration modules might be tapping power from the cigarette lighter jack - I just don't remember where I hooked them in. Since everything is being done with harnesses designed for the car it's quite possible all of them are on the radio line though too.

It doesn't help with the battery being under the back seat because I can't find any discernible pin switches for the door so I was just hanging out in the back for 5-10 mins each time watching the meter. It gradually went down from about 4 amps to 2 then to 1 and hung at about 450ma for a long time then I heard a relay click and it dropped to 120ma and there it sat. This was all within I'd say about 5 minutes - certainly under 10. If what you say is accurate then it's a good likelyhood I don't have a significant drain if everything else shuts down eventually.

I'd have to test if leaving my meter in line with the meter turned off if it would break the connection or if things would stay connected. I could leave the meter connected overnight and turn it on and check the reading in the morning.

Yes, I've got enough knowledge to understand the basics - took electronics courses in school many many moons ago.

Rich

So, you've hit on the exact reason for using the battery disconnect switch (or parasitic draw adapter). With the battery disconnect switch engaged, current will of course continue to flow through. The ammeter is connected across each side of the switch so when closed, the meter leads are shorted and will read 0mA. Once all the modules go into sleep mode, the switch is opened, but since the meter is connected across the switch, it maintains circuit continuity so the modules don't wake-up they way they will with a battery reconnect. With the switch open, the meter will now indicate the resulting draw. I'm kind of surprised that the fuse in your meter didn't blow when you connected in inline with the battery and battery cable. The immediate spike in current draw from the battery when everything comes on again, I'm sure probably exceeds 10A. This is the other reason for the switch, so the immediate power-on current draw isn't through the meter.

If you have a DVM, these also tend to go into sleep mode so if you left it overnight, you'd likely have the same problem. Turning it on would be like reconnecting the battery. An older analogue meter is a better choice, but not very common anymore. Having said that, if you use a battery disconnect switch, there would be no need to leave everything on overnight or to worry about the initial spike in current draw.

I'm assuming that since the majority of members here are in the US, you probably are also. Somewhere like Harbor Freight Tools will have an inexpensive battery disconnect switch that you should be able to use. You'd only need to find a way to securely attach your meter leads to each side of it. The only real difference between a battery disconnect switch and a parasitic draw adapter is the the "official" adapter has a small post on either side of the switch to clip meter alligator clips to. Otherwise, the function/purpose is identical. The genuine parasitic draw adapter is probably about $80, while a cheap battery disconnect switch is probably about $5. If you're here in Canada, Princess Auto also sells a cheap version of the switch. Amazon is yet another option.

Depending on brand of disconnect switch, you 'may' also need to purchase side post battery posts to screw into the battery in order to connect the switch. As for the switch shown below, I enlarged the hole in the one end of the switch and tapped a thread to match the factory battery cable so I could screw it on directly. There isn't a lot of metal there once it's drilled and tapped, so a great deal of care is necessary if you were to do it that way.

https://www.amazon.ca/EKYLIN-15-17mm-Di ... 276&sr=1-8

https://www.amazon.ca/gp/product/B0049B ... UTF8&psc=1

As for your current measurement, 120mA is certainly higher than you'd prefer, but it's certainly not like a couple of amps by any means. This could suggest you have an intermittent fault somewhere. I certainly don't envy you having to track down something like that.

Also, be sure that as you pull fuses looking for a high-draw circuit, to NOT reinstall them. This will result in any module on that circuit to wake-up/power on again and skew your results. When all is said and done, you should have no fuses installed anywhere by the end of your test.

Have you had any other electrical issues? Slow to crank, dim lights, etc? It may also be that if you have a poor connection (which sometimes occurs from corrosion under the boots of the battery cables, or other areas in the vehicle), or your alternator is not working correctly that your car eats batteries over time because it's just never being charged properly.

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This will give you some info on my car - check this thread out: http://www.pontiacbonnevilleclub.com/forum/bonneville-gxp-northstar-powered-cars/topic52215.html
And here: http://www.pontiacbonnevilleclub.com/forum/bonneville-gxp-northstar-powered-cars/topic52359.html

I didn't hit the 10A draw because I was very careful to make sure before plugging it in that all doors were closed etc. It pulled about 4.2 Amps when first plugged in.

I have killed 3 batteries so far thus the need to find the drain. To be fair though for each of those times the car was setting for long periods of time and the battery cable should have been disconnected but was not. As to the reason why, the topic I linked to will explain. As part of the repair I had a new Alternator and Starter put on the system. Battery terminals are corrosion free as are any of the terminals I can see under the hood. I don't know about the ground connections as I don't know where all are or if I can even see them from the top side.

I just had the charging system tested and it came out OK. I also found that the car apparently checks the charging system and notifies you via the DIC of any electrical charge issues so if my alternator was bad it would have likely told me.

Thanks for the links - I will check those out .. as you mentioned I would need to get some side posts to screw into the battery.

Rich

The charging systems in any of these newer cars (and that's a relative term) is much more complex. There are several factors that determine alternator output to charge/maintain the battery. Although there is certainly some diagnostic capability with the charging system, failures do occur without warning on the DIC. It just depends on what the problem is. It sounds like you've covered this reasonably well. I read through the other threads and do recall the problems you had after the rebuild.

My Bonneville is both in winter storage, and has had many electronic mods that make it a poor candidate to provide you with any test measurements. I've got no idea what the aftermarket devices you have installed draw when idle and this is probably the biggest variable. 120mA draw when the car is a daily driver is unlikely to cause any big problems. Between an aftermarket stereo, chime module and remote starter, this may be quite normal. I can try and find the table I once had that provides approximate current draw for all GM's different modules when in sleep mode, but it may take me a while and I'm also not sure that with 50 versus 120mA it would really be all that helpful. It is fairly well know that leaving a battery connected for prolonged periods without being charged will take a toll and over time and will cause the battery to fail to the point it can't be recovered. What type of batteries have you been installing?

Here's what I would likely do...

1. Buy a battery disconnect switch, modify it be used as a parasitic draw adapter and confirm current draw after 30 minutes of the car being powered off and being left completely idle.
2. If the draw seems high, really try to isolate all the aftermarket accessories and perform the parasitic draw measurement again.
3. Have the battery tested again (this one too may have failed simply due to draw over such a long time without regular use), possibly try replacing it with a high-end product.
4. Use the car as a daily driver for a period of time and see how things go. Monitor battery voltage when you park for the night and also just before you start it first thing in the day. If you have an intermittent problem, you may notice a large drop overnight that otherwise wouldn't be suspected with a low parasitic draw.
5. If problems persist, start by leaving all the aftermarket devices disconnected, fully charge the battery and try again for a few days.

Over all the years I've had a Bonneville and been around the forum, I'm not sure that I can recall a single instance where a member ended up having a problem due to parasitic draw from an OEM module. I'm not saying it can't happen, it just isn't common in these cars. I have a huge mistrust for aftermarket electronics due to so many issues over the years.

Currently the car has a Duralast Gold which I found out after purchase that they are really kinda junky batteries. Fortunately this battery is their best one and has a 5 year warranty. This is the one that I just had replaced this week. Prior to that it was a battery that I purchased through a local chain store in the MI, IN, OH area (Meijer) - they have since discontinued carrying batteries. That one was replaced under warranty once and then I got a pro-rated refund upon returning it a second time since they no longer carry batteries. In all situations though the battery died due to long lengths of time sitting without having had the battery disconnected and having (well apparently a 120ma) drain on it. Perhaps as you have said if it's a daily driver it will likely not be a problem. Had no issues today after sitting all night.

I think I'm going to take your advice and look into a disconnect switch to make things easier to troubleshoot.

It's doubtful there is any issue with the battery - it was just replaced a few days ago.

As for pulling the fuses I had the thought to just pull them and not replace them but I was a little afraid of getting the right fuses in the right locations. I know there is a map so I should be okay.

I think my first step though should be to get the disconnect switch and take a look at it after it's been off overnight. I just need to get my head around how they work.
Rich

since your draw is within spec, I would suspect the charging system.

you eat batteries, so, just for fun, probe the alternator and check for a/c current.

maybe the alt. is funky: I would get it checked first

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

The old one maybe - the one that is currently on the car now is pretty much brand new. It was replaced as part of an engine rebuild a few months back. I had that, the starter and the a/c compressor all replaced.

My battery disconnect switch should be here today so I plan to do a little more thorough investigation.

It would be helpful to know what happens when the door opens if anyone knows. I'd like to pull those fuses so that it doesn't turn things on when the door opens since the battery is in the trunk. I can't see any signs of a pin switch for the door - looks like it might use some sort of magnetic detection.

Rich

There is a mechanical switch for each of the doors, however they are embedded in the door latch mechanism. When you open/close a door, the switch triggers an input on the respective door module (there's one for every door, but the trunk is different). The module (if asleep) will wake up and generate activity on the Class 2 Serial Data Bus which results in pretty much everything waking up. As far as disabling the door modules, there is a single fuse in the read fuse block (10A) labeled "RRDRMDL" that supplies power for the electronics of both rear door modules. The power windows in these doors are protected separately, but it isn't necessary to worry about pulling that circuit breaker.

As far as how the parasitic draw adapter works, it is simply an inline mechanical switch placed in series with the negative battery cable. When you turn the green knob (as seen in the Amazon link), two contact surfaces separate and the circuit opens cutting power to the vehicle. With a ammeter placed across (in parallel) with the switch, it is shorted when the switch is closed. Once you open the switch, current then flows through the meter. Because the meter is part of the circuit the entire time, the circuit is never broken. Current simply flows through the meter now instead of the switch. This means that, since the circuit is never broken, the car remains in sleep mode and you're now measuring the resulting current flow.

In regards to fuse position, there is the legend of course, but a quick picture with a digital camera is also a great option. You'll want to pay closer attention to the under hood fuse block because of the two used to protect the accessory outlets. These fuses of course can be placed in one of two positions depending on whether you want power supplied to the outlets constantly or have it turned off once retained accessory power shuts down.

_________________

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Right but accessing it in sleep mode is the trick if you have to open the door.. I suppose I could just leave the door open (it's garaged) - or are you saying if I pull that fuse that I'm good?

Rich

you can pull the fuse for the interior lights - courtesy

and be sure the twilight sentinel is set to off or minimum time.

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Yes, if you pull the fuse, the rear two door modules will not be powered up. Since the latch mechanism switches are connected to their respective modules, and the modules are powered down, there will be no activity detected.

Leaving the door open is the alternative, and also factors in that you can rule out those modules as a source of the fault. Just make sure to leave them both open so you can easily access either the switch, or the fuse block.

Edit: Grammatical improvements.

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This will not solve the problem of preventing the modules from waking the data bus. Interior lights are controlled by a completely different module.

_________________

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Yes, thought about that too. Don't think the twilight sentinel has anything to do with the interior courtesy lamps does it? I thought that was only for headlight control (staying on after exit vehicle)



Good call - I usually take pictures of everything - didn't even think of it duh!



Good enough - I'll give it a try

You are correct, that won't help. Interior lights are controlled by the Rear Integration Module via data bus communications. Twilight Sentinal doesn't even factor in with this. If you pull the applicable fuse, the lights will go out, but there will still be a flurry of activity on the data bus because the door module(s) will still sense the door opening and send out all the applicable messaging.

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Man and this was in 04/05 .. I can't imagine how complicated things have gotten with 2019/2020 vehicles...

Rich

The technology in these cars is actually very impressive for the time. This actually applies to all the Bonnevilles (and others) from 2000 onward, pre-2000 in some Cadillacs. The great thing is, for the most part, it's been very reliable. You should read about the stuff that happens when you pull the door handle of the passive keyless entry in the 2005+ STS lol!

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Ok I'm baffled probably due to the way this car works. I lost 150ma when I pulled the #37 fuse (HVAC BATT(10A)) - it comes back when I plug it back in... however I was still at around 560ma draw at the time. I kept pulling fuses and I pulled the #7 fuse (DVR MDL (10A)) and it dropped to 40ma. I plugged it back in and it jumped back up to 1.24A then down to 560ma and then down to 40ma. Don't know if that means driver module (driver door?) but all lights were off and both driver and passenger front doors were closed. Rear doors were open and closing/opening made no difference because I had the module fuse pulled. I don't know if I should just start putting them back in one by one until I see a jump? That may not be accurate either if some module wakes up when I plug it in and then goes back to sleep.

What do I do?
Rich

It's just really important to A) make sure the modules are asleep (manual suggests minimum of 15 minutes inactivity for most vehicles, although somewhere I recall reading 30 minutes) and B) to not do anything that wake up the modules while performing the test (i.e.: replace a fuse or relay that has been removed).

Here is some abridged information from the service manual. Note that J 38758 is the identification of the GM parasitic draw adapter tool. I've added "parasitic draw switch" in front of each reference just for easier reading.

1. Set a digital multimeter to the 10A scale.
2. Connect the digital multimeter to the test switch tool terminals.
3. Turn the parasitic draw switch (J 38758) knob to the OFF position. The current flows now through the digital multimeter.
4. Wait 1 minute. Check and record the current reading.
4.1 When there is a current reading on 2A or less, turn the parasitic draw switch (J 38758) knob to the ON position. The electrical current will now pass through the switch.
4.2 Then switch the digital multimeter down to the 2A scale for a more accurate reading when the parasitic draw switch (J 38758) knob is turned OFF.
5. Turn the J 38758 knob to the OFF position. Wait 15 minutes for most vehicles.
6. Check and record the current reading.
7. Note the battery reserve capacity, amp hour rating. (LD8 engine book spec is for 800CCA and 140 minute RC).
7.1 Divide the reserve capacity by 4, amp hour rating by 2.4.
7.2 Compare this to the multimeter milliampere reading taken in the previous step. The parasitic current drain should not exceed this number. Example: If a battery has a reserve capacity of 100 minutes, (60 A/H) the current drain should not exceed 25 mA.
8. If excessive current drain is not found at this time and there are no other apparent causes, complete the following:
9. Using the MIN/MAX function of the digital multimeter, monitor the parasitic drain overnight or during the day. This will determine if something has been activated during that time frame.

The battery run down time will vary depending on cold cranking amperage (CCA) and reserve capacity (RC). If the CCA and RC are higher, then the battery run down time would be longer. If the CCA and RC are lower, then the battery run down time would be shorter. The graph below indicates roughly how many days a 690 CCA battery with at 110 min. RC (60.5 AH) starting at 80 percent state of charge will last with a constant current draw until it reaches 50 percent state of charge. Differences in battery rating and temperature will affect the results.

25 mA / 30.5 days
50 mA / 16.5 days
75 mA / 11 days
100 mA / 8.25 days
250 mA / 3.3 days
500 mA / 1.65 days
750 mA / 1 day
1 A / 0.8 days
2 A / 0.4 days

I'll continue to see what other reference information I can find that may give a more specific list of expected current draw.

_________________

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