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OK Folks,

Time to bug you all with a very specific problem.  I searched the forum and could not find info on the vehicle/problem specific enough to give me a direction.

The car is a 1995 Fleetwood Brougham.

Ever since I have owned it (9 years) it has had a problem I just worked around, by driving it at least once a week.

The dreaded "Parasitic Power Drain".

Yeah, been dodging that one.  Best fix known to man - drive it.  But this week the battery went dead in 4 days.  I have seen signs of fluctuation in severity and have been generally observing it all this time and poking around here and there.  I didn't get lucky in those efforts.

So today I opted to actually do a voltage drop test at the fuse box before getting more involved with relays, actual amperage draw testing etc.  (Who wants to reset all the radio stations?)

So... As a reference I chose the CCM Bat feed as a baseline measurement (inferred acceptability).  At the fuse, it fluctuated between pulling .6 mA and 1 mA.  I went with 1 mA and after referencing this table: fuse-charts.pdf (powerprobetek.com I see this translates to a draw of 135 mA. (inferred acceptability)

With that in mind I went through all the fuses.  A few were pulling some current. All of the problem candidates are listed below. (read from right to left maybe)  I think you will agree one circuit stands out.  Power Locks.

mA Result    Circuit    Fuse Amperage    Milli Volt measured
1713           PWR Lock        20                              5.5
135            CCM bat           10                               1
127             RAP Bat            25                             0.3
93              Park lts             20                             0.3
11               HVAC Bat         10                              0.6
27              Tail lts               10                              0.2
212            Wiper                25                              0.5
            
2318    Total drain        

So, my question:

Have any of you folks, especially the long time Caddy techs, seen this and might you be able to tell me where to go, other than to h***.  LOL.

I know I have to get into the weeds on this.  I m just hoping for some direction to start with.  The locks all function as designed.  There is no obvious problem.  I am not in the mode to tear into all the doors but may do so eventually because I want to get inside the RR door anyway.  

Meanwhile, I am pulling the power lock fuse to see what that buys me.  I don't think I need to get into testing amperage draw while pulling fuses.  Unless one of you tells me different, I think I have my culprit.

Thanks in advance for any ideas and if you want to shoot me for asking this question, please do.  It will save me some work.

RC 

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I just went out to pull that fuse but decided to do a Bad Alternator Diode Test first.

I'm assuming you may know what that consists of.  Easy stuff.

My smallest AC scale on my DMM is 200V.

I should see no more than .5 AC voltage at the battery.  (black on black, red on red).

My meter displayed 31.2 volts!  I don't know if I can believe it.  I see none of the usual signs of this problem like fluctuation lights, etc.

Any thoughts on this would be appreciated.

I have not pulled the power lock fuse yet because now it's guilt is in doubt.

Thanks!

RC

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If the battery goes dead after 4 days of inactivity, the alternator, although it may not be performing to spec, is a separate issue.

The door locks may be an issue if one of the lock actuators is not completing its lock/unlock and is still trying?

I recall having a similar sticking seat issue where the power seat was basically stuck trying to move & soaking up power.

Bruce

2016 Cadillac ATS-V gray/black

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Long shot here but can you confirm your meter has a good battery. When mine have a low battery it will read high voltage like that

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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@ Bruce - Yeah, I'm thinking 2 separate problems here.  I want to double down on the alternator test before going that route.  Those things are expensive!  (figures)

@ Rockfangd - Good thought.  It hadn't occurred to me.  I will put a new battery in it tomorrow and give it another shot.  Part of that double down thing I mentioned. 🙂

Does anyone know which particular service manual I want to track down for the power locks?  Looking for electrical specs so when I get into the doors I know what the solenoids should test at.  I think this is going to be a case of pulling it in the garage and opening up all four doors so I can isolate one at a time if necessary.  Have to see what is going on in the RR door with the window regulator anyway.  The window has lost it's ability to stay level.  lol.

I will report back on the alternator test tomorrow.

Thanks guys.

RC

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The Helm shop manual is the one to have for maintaining your Cadillac.  Watch ebay or other used sources that may offer at a discount, but also know what they are new for comparison.  I have seen used shop manuals offered for more than new prices.

Bruce

2016 Cadillac ATS-V gray/black

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Got it.  Thanks Bruce.  I will look that up and shop around.

So, I put a new battery in the DMM as Rockfangd suggested and redid the diode test.  Good call Rockfangd!  It read 8.2 AC volts across the battery. 

Reading up on the ramifications of that and it seems clear to me the first step needs to be a new alternator.  Showing that AC voltage (more than .5V) indicates a blown diode in the alternator.  When the car is running it just results in dirty power.  But when it is shut off, the blown diode will allow current to backfeed throughout the car wherever it can go.  Last night a neighbor came over and we were hanging out in the garage.  The Caddy was outside with the hood up.  After about 10 minutes the under hood light turned off.  As it should.  But after 30 seconds or so, it came back on.  Rinse and repeat.  Totally made me more suspicious of the alternator theory and the retest today nailed it.  Obviously all kinds of circuits are getting wake up calls when the accessory power is supposed to be off.

So I can't trust the results of any of the circuits the voltage drop test pointed to.  If the problem persists after the alternator replacement I will revisit that and hopefully I will have landed that manual Bruce mentioned, by then.

I know some of you guys don't need all these details but I put them here for others that may be searching for the same problem one day.  Sorry.  🙂

And besides.  I have been driving and repairing cars for a long time now and this the first time I have seen a bad alternator function for at least 5 years.  It was about that time when I had another situation where I had to rely on that 10 minute accessory power cut off (a whole 'nother saga involving the security system and a body shop that was sloppy) so I know for a certainty it is supposed to go dark after 10 minutes with the key off.  Not go dark and then come back alive like I saw last night.

Thanks guys.  I will drop a note here when I have the alternator in place and report if it was the fix.  Again, for reference for the readers out there.  Hope so at 300 bucks! AC Delco.  It is on order and will be here on 5/4.  I'd rather drop 300 bucks than tear into the doors anyway!  Fingers crossed.

RC

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Sometimes the alternator will be slightly warm when that type of failure has occurred. Glad to hear you are on the right track

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Actually yes!  It was warm.  I noticed it the other day.  Man, if only all this knowledge could be put in one place...  Wait...  Can you say CaddyInfo.com?

Seriously, there is so much value to this site.  I try to respond to queries when I can but I only do so when I know it is correct and not some assumption that I dreamed up because I may have lucked my way through a problem.

Thanks,

RC

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Honestly. In todays day and age so many people are quick to judge based on what they read or hear, But suggestions and replies are a huge help to others. Even if it is not correct it can still help. Sometimes members can be 1000 miles away. Without seeing the car in person things can get difficult.

This forum is full of strong members. Any suggestions are highly appreciated

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Hi guys sorry for not noticing this post before tonight.

I have the unique privilege of having built a custom Art car from a retired police car.

The B -Body and G body are essentially the same chassis with and extra 10inches of length added behind the drivers seat.

I used a complete harness and all amenities from the Fleetwood in the Caprice.

So I have run through the entire harness and merged.

That power drain of 5mA is the delayed accessory buss controller pull the module and check again.

However it never caused a battery drop below 11 volts for me so I always started. I was using a Optima Red that is kind of like a battery backup battery in it's discharge curve.

If you had 8VAC on the battery during running there was probably a drain through the same bad diode module not measured.

The cop cars came with a larger 138A alternator and a different drivers side bracket to support the big alternator with the heated front windshield option for the L91 caprice this bracket and alternator can be had from dealer as recent as monday a week ago. It uses a longer belt as well I installed one on my suburban.

Also that noise in the AC is called slugging I worked for PRO at that time and we had hundreds of complaints but just replaced the compressors during the warranty rather than issue a bulletin. What the issue is , there are two versions of the R4/R11 compressor the R11 has about 50% more displacement but physically the same size. The larger evaporator on the Fleetwood and second Rear AC on  Escalade and Suburban causes liquid to be present on the suction side of the compressor when using a R4 in place of an R11. Hense slugging and compressor failure. 

If you have the noise then you have a couple of options On g-Body you can swap out the evaporator with a B-body on the GMT400 Escalade and Suburban they went to a Sankyo compressor in 1996 junk yarding can find the complete bracket set , hoses and pulleys for about $150 the Compressor for 60 on amazon

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You are correct about the compressors. Simple term is like hydro locking the compressor. Nearly every GM compressor I have seen fail was because of that. Either burns out  the clutch from over working it, or wrecks the the compressor internally and distributes through the system.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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OK.  Alternator is in the car.

.04 VAC shows at the battery when idling.  Within spec and far less than the 8.2VAC the old alternator showed.

I also checked for current on the power lock circuit doing the voltage drop test as before.  0 mV.

My fuzzy radio is also cured.  I had attributed that to the power antenna, possible a problem with the antenna lead(s).  Just never found a reasonably priced antenna or anything else wrong.  Been that way since 2015.  lol.

So.  Time will tell but I believe my problem is solved.  Still cannot believe it was the alternator all this time.  smh.  Now I have to let it sit for a week or so and see if it cranks.

Thanks All, for your input.

RC

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  • 2 months later...

OK Folks... Time to revive this thread for a sequel.

Recap:  I had found a substantial drain of 1.7 A on the power lock circuit and a bad diode in the alternator causing 8+ ACV showing across the battery and potentially allowing "leakage" back into the car.  Replaced the alternator and the AC went away and so did the drain on the power lock circuit. 

Whew, problem solved.  Well not quite...

After replacing the alternator it took 6 days for the battery to go dead.  I whipped out the old fashioned hydrometer and every cell tested dead, even after a full charge.  OK, all that AC voltage smoked the battery.  I can believe that considering the guy at the parts store commented that I'm lucky that much AC didn't damage electronics.  Off to Advance Auto for a battery I go.  They tested the battery and said it was good.  I debated that point and they debated the remarkable technology in their testing equipment.  Then I told them to put a battery in anyway.  Got home and whipped out that hydrometer again.  Every cell in the new battery tested alive and well.  I was satisfied.  Let's see what happens. 

Since then the battery still dies.  It can take a week or it may take 2 weeks but eventually, it is dead.  Been hands off for the last few weeks cuz I am tired of it.  lol.  (I hear ya Rockfangd).

Finally over the last week I got back into it.  Put the DMM in series on the negative battery terminal and looked at the draw after the a 10 minute wait for the systems to all shut down.  It fluctuated between .13 and .14 A.  I pulled fuses to see where the culprit was.  I pulled the CCM BAT fuse and it fell to 0 - .01A.  Replayed a few times to be sure and to allow time for a beer or two to go away.  Got my culprit.

BTW.  Take a look at the numbers I posted at the start of this thread.  CCM BAT was the 2nd highest draw at 135 mA.  Nice to know some things don't change.

I am on the hunt for a CCM now as I believe it either has a short or some component inside has failed and it is activating something, likely in the security system and maybe even those door locks, running the battery down.  It is an awful complicated mess as it involves the ignition key with the resistor in it and the CCM being programmed to expect that resistance.  So I am in for fun and games when I do find a CCM.

I may have found one.  I will know tomorrow (8/4/21).  The deal hinges on whether they can provide me the key to the car.  Thanks to the internet, I have seen pics of the car and the key was in the ignition and bent.  So I hope they don't try to fool me.  The car was in a wreck and I don't think the driver fared very well unless they were real short.  Looks like it drove under a semi and became a near convertible.  I can measure the resistance of that key and buy a couple matching blanks and have them cut as a copy of my current key.

As far as buying a CCM goes?  Not happening.  GM quit producing them at least 15 years ago (wouldn't want to pay that anyway).  Cardone used to re-man them but they have none.  And man, they are near impossible to find in a boneyard.  And then you have the key hassle.  I talked to Cardone and if I was able to get one from them I would have to put it through a learning procedure after installation.  It takes 30 minutes and involves crazy gyrations of turning the key on and off repeatedly etc.  But the end result is that in the process the CCM learns the resistance of the ignition key and you don't need to replace the key.  I managed to extract a document out of them explaining that process so I got those goods.  I could not get out of them if that relearn will work on any CCM or if they flash the ones they re-man with the code to make that possible.  I will attach that document here for whoever is unfortunate enough to have the same problem.

I also talked to the local Caddy dealer.  They had to have a séance to ring up a tech old enough to be familiar.  Got a whole bunch of "maybe's" and a possible price tag of 3 to 6 hundred dollars for me to bring them the car, new parts, old parts and permission to spend hours figuring it out.  No thanks but I think I got what I was looking for.  Listening in between the words I heard him say that some systems need to be flashed, some have a re-learn process and others need to be opened up and cannabilized.  Well, I know there are 3 possible systems.  I know mine is the "Passkey II" system and I know the Passkey II is the one that uses the relearn procedure.  So, I think, if I have to buy a used one with no key I can do the re-learn and teach it my original key's resistance.

I think being the key words...

Now that I have made you guys read this book my question for you is:

Can anybody tell me if they have seen the CCM BAT circuit pull current when the car is off and powered down and it WAS NOT the CCM itself? 

Side note:  All wiring I have looked at is pristine.  I have not found a damaged wire yet and have been inside 2 of the doors and all but removed the CCM during the process

of looking at grounds and/or signs of wear or damage.

Good grief.  File size limits prevent me from attaching a 4 page pdf file.  I am putting page 1 here and will see if it will let me put the rest in subsequent messages.  If not, this will just be a tease.  Feel free to email me directly and I will send you the whole 4 page doc!  

Again, my question for you is: Can anybody tell me if they have seen the CCM BAT circuit pull current when the car is off and powered down and it WAS NOT the CCM itself?

Thanks folks!

RC

ReLearn1.JPG

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Are you referring to the TDM (Theft Deterrent Module) Just want to be sure. I need to look more into the fuse description. I don't know why but the first thing I think of when I see CCM is Climate Control Module. 

Where is this module located on yours?

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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The Climate Control Module is used on Sevilles and Devilles but not Fleetwoods.  On Fleetwoods the CCM is the Central Control Module (thanks GM) and is located in the trunk on the support behind the rear seat (left of center).

On 95s and 96s, the TDM (Theft Deterrent Module) is incorporated into the CCM, Central Control Module.

In 95s and prior the TDM was a separate module under the 3rd brake light.

The CCM, Central Control Module's job is to control lighting, security and to evaluate the resistance of the key that is in the ignition.  If that resistance is what it is expecting it sends a signal to the PCM, Power Control Module, under the hood, saying "all good, start the engine". (Until that signal is received, the injectors are turned off)

Those screenshots above are what Cardone requires to be done when you install one of their re-mans.  It programs the unit for the resistance of the key in use.  What I am trying to figure out is if that re-learn process will work on one taken out of a wrecked car.  In other words, does Cardone flash it with the necessary code or is it there on all of them?

Darn things are not cheap.  Found one 150 miles away that would have cost 160 bucks, shipped, but the next day they told me they no longer had the key (someone bought the entire column).  That key was going to give me my "plan B" in case the re-learn process was a fail. (measure resistance, buy a blank that matches, go to ACE and cut the blank to match my key)  Those blanks are readily available on EBAY.  There are 14 or 15 different varieties, difference being the resistor value.

But I am not gonna throw 160 bucks at it to end up with a matching pair of paperweights.  I tried negotiating with them for the one with the missing key but they would not play so I said "See ya".

I cannot find a definitive answer on the internet to the question "Will the re-learn work on any Central Control Module, used, re-man or new?"

Thanks for your input.  If you find out more than I can, I owe you a beverage.  All those details I have described above are not from some tremendous box of details in my head.  It is from reading billions of articles and blogs on the internet.  My wife says the car just refuses to be fixed.

LOL.  I do look forward to hearing back!

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Thank You for clearing that up. 

So basically like the E/K platform that uses the IPC as the (Master Module)

Don't give up. The Fleetwood is a wonderful model.

I need to look into all of the circuits on that module. I would lean more toward something controlled by that module rather than the module itself.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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More detail for you:

The car has a power drain of 135 - 140 mA.

That first dropped to 0 when I pulled the big 50 A fuse under the hood labeled BODY 2.

So then I identified all the circuits serviced by that fuse.  They are:

RAP BAT, 
HVAC MDL, 
ELC SENS, 
D/INT LTS, 
FRT CIG, RRCIG, 
HVAC BAT, 
CCM BAT, 
PWR MIR

They all test good (no draw, no change on the meter when pulling the fuse) except CCM BAT.  As best as I can determine, that is simply the power feed to the computer.

There was also a circuit breaker (RAP RLY) that is serviced by BODY 2 and it appears that breaker sits between BODY 2 and all the circuits I list above.  Like an insurance policy?  I replaced it anyway with no effect other than eliminating the doubt.

I did pull all other fuses.  None produced any change on the meter except CCM BAT.  And when you consider that pulling the CCM BAT fuse results in the draw dropping to 0, there is not a lot of room for other things to get in the mix. 

Hence my question "Can anybody tell me if they have seen the CCM BAT circuit pull current when the car is off and powered down and it WAS NOT the CCM itself?"

I'm not giving up.  It isn't in my nature!  LOL.

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As I re-read this it becomes obvious that if it isn't the CCM itself, then there has to be some sort of short in the wire(s) running from the BODY 2 fuse to the fuse box and then on to the CCM.  Given that it is a relatively small drain (~135 mA) it seems unlikely that it's a wire problem.  It would seem to me that would result is something more like a dead short.  Or erratic behavior like you would see with a broken or frayed wire.  This draw is rock solid at 135 - 140 mA.

Or am I being optimistic or jumping to conclusions?

All wiring I have looked at so far has been pristine.  I have found nothing but a little dust.  But I have not traced every inch either.  It just doesn't seem likely and I hesitate to possibly introduce more unknowns by getting down and dirty with the wiring.  Dangerous assumption?

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Ok a few things here.

Did you check the reading with that RAP relay pulled? Being it is shared with that BODY 2 FUSE.

If you can go to the CCM and feel it. (Warm) when system is asleep.

I would be removing, cleaning, and reinstalling the Ground(s) to the CCM. A poor ground will surely cause weird issues.

Unplug each plug to the CCM and inspect them. Make sure the pins are completely intact, clean, and not burnt

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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