I know there are threads on here about this problem. That is how I found out about this and learned how to test for it. Below is a run down of what I have done so far. I am kind of lost now.

Bought a 2004 C5 Convertible about a yr ago. A few months ago battery started to die on a weekly basis. Then it started happening sooner and sooner. I would be lucky to get 3 days.

After reading several threads I tested and found that I was having a parasitic draw. I don't remember the exact numbers but here is what I have done.

Tested all fuses under hood and always had about a 2.55 amp draw after pulling one at a time.

Went to the footwell panel and as soon as I pulled (if I recall) #4 SCM the draw dropped to .011 amps. So here I found the problem! Well so I thought.

I purchased a new SCM and installed it only to find out I needed to get this "flashed". I have not done this yet. I am permanently disabled so funds are very limited. The only thing that was fixed after replacing SCM was telescopic steering wheel.

So I decided to just set the seat where I was comfortable and keep the fuse out. No fuse no draw.

I stopped at this point about 3 weeks ago.

NOW.... for the past week the battery is dead again after 2 days. I can drive it on a regular basis each day and it will still be dead. Tested both battery and alternator months ago and again just the other day. Both are good. DIC shows 14.1 charge.

Just yesterday I noticed it was lagging a little when I started the car. I put it on a charger while I washed the car. 2 hrs later I started it sounded fine and went to wash other cars. Then 2 hrs after moving vette I got in to start it and dead. Not even a clicking sound.

Now I stopped doing the parasitic draw test after it dropped to .011 after pulling #4 and never tested any of the other fuses in the footwell panel. Figured with the amps dropping to almost nothing now there was no other issues.

I am pulling my hair out trying to get this fixed. Now my time is extremely limited dealing with my mother in law. Brain Cancer. Not sure how much time we have left with her. Any help would be GREATLY appreciated.

When I was researching my problem on this forum I remember a guy in Huntington Beach, CA who I think was a mastermind when it came to the cars electrical system. I remember the HB part only because that's where I grew up. I know Bill Curlee is good as well and have sent him a PM already.

Thanks again and look forward to meeting a bunch of fellow vette owners and friends.

Tim

 

OK, we're here to assist. It is apparent you found a problem but it appears there is at least one more. We need to go back and figure out where it is. Here is my guidance on finding a drain. You probably only need to look at what I say about actually separating the two fuse boxes to locate the fundamental location without pulling fuses and relays.


Process for finding a parasitic drain:

Suggest you remove the hood light bulb first so it does not provide a drain.

For measuring battery drain I would hook up an ammeter to the negative side of the battery by removing the negative cable and measure between the cable and the negative battery post.

When you connect the ammeter the car should draw several amps until it goes into "sleep" mode which can take several minutes. Normal sleep mode drain should be between 17-22 milliamps. You will need an ammeter that can transition from whatever the drain is down into the sleep mode. If you have a drain I suggest the following:

Once you determine you have a drain with an ammeter what I recommend first is to listen to each fuse box and see if you hear any relays operating. If not, then place your hand on each relay to see if any of them feel hot. That can be the start if you find something like that is happening.

If nothing shows up you can hear or feel then I recommend you separate the two fuse boxes from each other. This is easy and done by removing the Red cable from the engine fuse box that feeds the passenger fuse box. It is on the right rear side of the engine fuse box. There is a stud there where the large Red wire from the battery connects. Just remove the nut and disconnect the large Red wire feeding the passenger fuse box and reattach the Red battery cable. NOTE: I would recommend disconnecting the negative ammeter hookup when working on the positive side doing this.

What you will be doing is measuring the drain with an ammeter to see if disconnecting the passenger fuse box causes the drain to go away or not. By depowering the passenger fuse box you will depower the BCM which controls the sleep mode so do not expect the sleep mode to happen.

If removing the feed to the passenger fuse box you then see you have eliminated the drain then you know it is something related to those circuits. If it does not reduce the drain then you know it is related to the engine fuse box. It could be a rare case where you have some drain via both fuse boxes and we can deal with that if you think it is the case.

Once you basically know where it is then you can remove fuses and relays to see where the drain is coming from.

PS: There are cases where the alternator causes a drain so it can be disconnected and see if the drain drops.

 

Are you positive you have a parasitic drain from a system in the car? Are you sure you actually have a good battery and that the battery cables are good and tight? Just mentioning the obvious... Testing for a drain before the car goes into sleep mode can really confuse the issue. Have you tried to disconnect a battery cable for several hours or overnight after a good drive to make sure the battery is first charged and then can hold a charge? Does the car have an aftermarket sound system? Mine did and until I started to remove it did I find out that it had a small amp that was wired hot all the time. Once that was remedied my power problems went away.

 

I do or should say did have a parasitic draw. Tracked it down to the #4 fuse which is the SCM. As stated I have replaced this module just have not flashed it yet. After replacing the module and replacing the fuse I still had a draw of about 2.55amps. With #4 fuse out amps drop to .011. So I have kept the fuse out till I could get module flashed.

I was ok for a couple weeks without having to charge the battery. Now it is dead (not completely car wont start) over night.

I had the battery and alternator checked less then a week ago for third time and both check out good.

Now for kicks I tried what CaseyJones above mentioned.

I have stock radio and cables have been cleaned and are tight. I had battery charging over night when I received his post. So I know it will not be driven for a few days I disconnected the terminals and charged battery to 100%. With terminals disconnected and letting it sit over night I just checked the battery and it has dropped to 76%. Battery been disconnected for 14 hrs. This to me does not seem like an acceptable drop over night. Any thoughts before purchasing a new battery.

Going to try and get SCM flashed next week. Do you think this will actually fix the original parasitic draw? Does flashing the module have that much of an affect?

Thanks

 

You have a battery problem. I have a battery in my shop that sat on the bench for 4 months and only lost .5 volts.

Would not think a new SCM would cause a drain even if the BCM needs a reflash/program to make it work correctly. You may have some other seat issue going on. Could be a motor is trying to run and the circuit breaker is only limiting current for a short time until it resets itself and allows more drain. This is not a uncommon issue.

 

I have never seen the need to RE-PROGREM the BCM for a SCM.. They should be a plug and play.

The seat: The drivers seat (if it has a memory function) will be told to go to a preset position. IF,, that position can NOT, be achieved, the seat motors will attempt to drive it there OVER AND OVER again.

The SCM has FUSES and "CIRCUIT BREAKERS" The circuit breakers are on the Passenger Foot Well Fuse Panel

The circuit breakers will trip and reset until the seat reaches its LIMIT or set point or the battery goes dead.

Turn off the MEMORY Function in the IPC Options set up screen.

The LUMBAR Air Pump Motor can also run when it isn't suppose to. If the bag is damaged or the air supply line is cracked, it can run and run and run.

If the Seat MULTIFUNCTION switch on the side of the seat is damaged and doesn't return to the center OFF position, it can cause the seat to constantly adjust. There is also a Diode inside the circuit board that can burn up or corrode and cause a constant current draw.

The seat motor feed back potentiometers are what tells the SCM when the seat has reached its Programed Set Point..
If the Pot is bad, it can continue to try to reach that point.

I have exercised the seat through ALL of the UP/DOWN FWD & REARWARD limits several times and cleared up position pot issues. Same for the mirrors position pots.

Check all of that out and see if it clears up the issue

 

Good morning Bill, I was reading another post when I saw yours. I do have the memory feature. I think I understand SOME of what you said but most of it went right over my head.

Going to get a new battery later this morning.

Are you saying that when I replaced the SCM there is no need to flash this? I am under the impression that I am flashing the SCM not the BCM. Was I miss informed here?

I don't work on cars very often. Just trying to keep from spending a fortune at the dealer. Everything worked 100% when I got the car and up to about 3 months ago. Memory function worked. When I turned car off seats go back to make it easier to get out. Before pulling #4 only thing that was working was forward and back.

When I pulled the seat to change SCM I didn't see any broke wires or any other issues under the seat.

Some of what you are saying about things running over and over is what seems to be my problem. I just cant figure out how to isolate this. Before becoming disabled I was a construction worker. Electrical on cars is something I know nothing about. Barely know how to use a multimeter. This is how little I know.

 

Okay I wanted to get some exact numbers and clarity to try and explain everything a little more detailed. I have tried a few things mentioned above from Dadaroo, CaseyJones and Bill Curlee.

Bills was pretty technical and a lot of it was over my head. So basically I started from scratch and below are the results. Mind you the new SCM is still installed.

Battery terminals disconnected and now have 100% charge.

Drove for 30 minutes to get lunch.

Removed bulb under hood and replaced #4 fuse. (Been out for a few weeks)

Now at this point with #4 fuse back in, only thing that works on the seat is forward, back, up and down. None of the 3 lumbar switches are doing anything.
Also the both memory features work and when car is turned off seat moves back and steering wheel moves to make it easy to get out. So everything works but the lumbar. These did at one time. Don't know when they stop as not a feature I normally use.

I did as Dadaroo mentioned and separated fuse boxes. Got a 0.00 reading. This tells me issue is in the footwell panel.

After reconnecting both panels I initially got a 2.10 amp reading. Then 30 sec later it dropped to 1.08amps

I pulled #4 fuse and the reading was 1.30 amps then 30 sec later dropped to .19 amp. This is 190 milliamps and is still high but is not in sleep mode yet.
I left multimeter connected from this point on.
1 min later it dropped to .12 amps
2 min later it dropped to .05 amps.
25 min later there was no change. It bounced between .05 and .06 amps. From all the posts I have read .05 amps is 50 milliamps and is still to high. I should only be drawing 17-22 milliamps.
Now I had both windows down to keep car from waking up. I reached in and removed several fuses, relays and breakers. #3 lumbar, #35 driver breaker, #18 HVAC, #27 HVACCON, #46 RRDEFROG, #36 pas. breaker, #28 radio, #23 BCM 2, #25 BCM 1. After pulling all these AND leaving them out there was no change. Still reading .05 amps.

At this point I opened the door. Wake up. reading .18 amp and ten sec later dropped to .05 amp. Mind you the BCM fuses are still out along with all the others mentioned above.

Replaced all fuses back and closed the door. Multimeter is going nuts!! It is bouncing from 3.81 to 3.95 amps. I reached in through window and pulled the #4 out again. no change multimeter going nuts. At this point we should be back to a reading of .19 amps like at the very beginning.

At this point I have become bald and hands are full of my hair. Suddenly about 5 min later I hear a noise come from inside the car. Didn't know what it was but thought I would open the door and sit down inside to see if I could recreate the noise. Come to find out the noise was the doors locking. Lucky I had windows down. Only one key and it was inside on the floor.

At this point I opened the door and start hearing the funny crackling sound by the battery which I have heard before which tells me the battery is dead!! disconnected multimeter reconnected battery terminals and sure enough battery is dead!! Barely enough juice to roll up windows.

Cleaned up tools, connected battery charger and came in to type this thread.

This is where I am at. Bald and confused!!

I want to thank all of you past and future for helping me with this. I hope we can get this solved soon.

Tim

 

I have NO Idea how you flash or program a SCM other than plug it in and use it. Its relays and switches and some diodes.

LUMBAR for a 98 C5:



SEAT Controls:




THERES NOTHING to flash or program....

It should just plug and play. Give it a try.


Try manualy moving the seat through ALL of its positions and to the limits several times and see if the seat is able to do what its supposed and designed to do. If it binds or fails to move properly,, that could be part of the issue.

Dont forget, you could have a bad Control switch.

Bill

 

I will throw this out there. I had a PAL interface installed on my C5 and started having battery issues. I talked to somebody here and they told me to clip a wire going to it. I took the PAL out and problem was cured. (PAL = Personal Audio Link I think) It allows you to plug in Ipod or Iphone to listen to downloaded music

 

Reading a schematic is over my head. Although let me ask you this. The 3 motors under the seat, do those have anything to do with the lumbar or they strictly for the up down forward back and tilt?

Took our Camaro in to dealer yesterday for key recall and asked about my issue. They said most electrical issues could take from 5 to 15 hrs to find. At about 150 bucks an hr this is not an option!!

 

Car is completely stock and has no aftermarket audio connections.

 

The upper schematic is purely for Lumbar and has one motor.

The second schematic is for seat movement and has 3 motors. 2 for vertical and 1 for Horizontal.

 

Thanks Dadadoo but I only have seen 3 motors under the seat. All 3 are identical silver motors and in line of each other. Was thinking about changing out switch on side of seat but that's another 150 bucks. Hate getting things to try and find out it didn't help. Still need to get battery. Going to try and do that today. Was on charger again over night and I barely turned over this morning. After 100% only showed 11.1 volts. Guess I killed battery by charging it every other day for past 3 months.

Will try to pull sea out this afternoon and look for 4th motor. Guess I just missed it. Thanks again

 

I had this same issue I feel your pain I don't post on here much but when I read the pulling your hair out part I needed to say something.
I had the same draw issue and kept coming out every couple days to a dead battery so I went through the same process that you are going through and couldn't find exactly where the problem was coming from until one day I heard a noise coming from my car it was dumb luck really. The noise was coming from the driver seat with the car being off for hours untouched this was strange to hear. My seats lost the lumbar function a little bit before the problem started and my seat functions started going one at a time so I hooked a multi meter to the seat with the car off and seen it was drawing power. I unhooked connection to the seat and poof the power draw stopped I even pulled the fuse just in case I been driving it a full year with no issue just can't adjust the seat which is not a problem because I am the only one who drives my baby anyway hope that helps some good luck.

 

We'll stick with you. This isn't rocket science and parasitic drains that are locked in are fairly easy to find.

Do you know how to use a multimeter to measure resistance and voltage? If not you at least need to get a simple one and look at some YouTube videos. We can talk on the phone if needed.