Troubleshooting a battery drain. I use 5-7ma with my courtesy fuse installed and still use 2ma with that fuse pulled. Does my PCM use 2ma? I may have to disconnect it to find out. But I'm asking if anyone here as measured their base load/drain with car shutdown and doors closed. That reminds me I need to disconnect the hood lamp.

What does the PCM use for current when shutdown?

 

thought it was 3 megaamps, im sure garydoug knows,,, lol. not sure how often he comes on site...

 

Rule of thumb is 25 milliamp. If you car had memory seat or any other options that are powered on all the time the it could be 75 milliamps Anything over 100 Milliamps 1/10th an amp) is an issue.

I believe a mega-amp is 1 million amps.

Common causes of draws is the Lighter, glove box light, trunk or hood lights.

 

Wow, so I've been chasing my tail here. I tried a google search on this and 25ma is conservative. Optima batteries tech advice says not an issue until parasitic approaches 100ma and 85ma is common nowadays.

So my 5ma to 7ma is actually normal and now I have to put all those connectors back together. Well it does surge when first connected and who knows how far using a digital meter but settles out at 5ma. Pull the courtesy light fuse though and it drops to 2ma.
Well I must have left a light on somewhere or a door ajar as I couldn't leave the batt connected for more than a couple of days w/o running the car. I guess I have to visit that test again soon.

BTW there is no open hood lamp - I looked.

Thx for the fast replies.

 

Well I did a little more trouble shooting as time permitted and found 2ma going to the Keyless Entry Receiver. Down to 2.8ma with that KER disconnected but I still see surge in current as soon as I connect my meter leads that settles down to 2.8ma. Current does not surge with the courtesy light fuse pulled and current is only 2ma. I'm thinking the surge is from the Courtesy Center module. I'll have to look at that next.

So I'm think'n do I want the KER and wireless lock/unlock on my car anymore? Save a little bit of weight and one less piece of equipment to break. Well 3 pieces if I remove the door solenoids also.

How 'bout the Courtesy Center? What all does that do? I never replaced the stereo after it got ripped out/off - even though they left me a good connector. Can the car function w/o the CC?

 

Im sorry, why are you worried about 2/1000 of an amp when you have a 600+ amp battery?

To kill a 600 amp battery in 24 hours you are talking AMPs draw, not miliamps. Even 100 miliamps would take a week to do any real damage to a good battery. I know nothing about how you are doing the tests. Have you tried disconnecting the battery? I have seen batteries with internal drains before. Finding a drain that can pull a 600 amp battery in a couple of days should be pretty easy. Finding one that drains the battery in 10 day can be a lot more challenging.

 

Well I'm curious here what the loads truly are as I know the PCM will need something to keep alive but where are the rest of the loads? Maybe it's the old school part still in me where the stupid clock used to be the only load. Most curious to find what loads I can live without. As car gets older removed parts/equipment are less parts to break. Also curious what all the electrical "boxes" under the dash are for and do. Getting familiar with the car for my own knowledge.

Now a remote hatch is very convenient but that's something not totally required either. Less equipment = less maintenance, fewer loads = smaller battery cycles/less batt/electric sys stress. Slowly converting the car for mostly performance rather than pick up groceries with. Not looking for comfort. BTW I already have a manual drivers seat to replace the more than stupid electric seat in it now.

So back to the Convenience Center, what does that all do? Can the car function w/o it?

 

Rest of the loads/current loads:
BCM = Body Control Module + VATS & key fob info + remote keyboard access
Radio = station presets & clock
PCM = Power Control module for drivetrain
Yes, under 85 ma is considered normal; 0.085 amp

 

You will need to pull a schematic and look, Its not something even a trained mechanic would know because it will vary year to years and manufacturer to manufacture. My guess since so many different things depend on the doors opening that it is ties the the body control module and the body control module and vats system may not like it not being there. So it could be as little as the radio does not get power to the clock to the car will not start.