Dead battery issues after installing the LMC5?
Thread Starter
Drifting
Joined: Jan 2003
Posts: 1,809
Likes: 10
From: ST LOUIS MO
Dead battery issues after installing the LMC5?
I'm suddenly having dead battery issues in my 04 Z. The only thing that's been touched on my car has been the installation of the LMC5 from compliance parts. I can't even let it sit 12 hours before the battery dies. The battery is good and I even threw in a brand new one from the shop.
Thread Starter
Drifting
Joined: Jan 2003
Posts: 1,809
Likes: 10
From: ST LOUIS MO
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
I never had any problems with my LMC5. Double, triple, quadruple check your wiring. I probed the 3 BCM pins that the LMC5 replaces, and IIRC none of them were hot when the car was off.
Also remove the column lock relay. You don't need it with the LMC5, and it might be shorting out.
Also remove the column lock relay. You don't need it with the LMC5, and it might be shorting out.
Thread Starter
Drifting
Joined: Jan 2003
Posts: 1,809
Likes: 10
From: ST LOUIS MO
I never had any problems with my LMC5. Double, triple, quadruple check your wiring. I probed the 3 BCM pins that the LMC5 replaces, and IIRC none of them were hot when the car was off.
Also remove the column lock relay. You don't need it with the LMC5, and it might be shorting out.
Also remove the column lock relay. You don't need it with the LMC5, and it might be shorting out.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You have to get the BATTERY CURRENT DRAW value measured!
Without that data, your shooting in the dark. Put a DC Current tester/meter in series with the NEGATIVE BATTERY terminal/battery cable and see what the BCM Sleep Current Draw is after the BCM goes to sleep (approx 5-12 min)
It should be right around 20 milliamps (0.02 amps) If its High,, something is staying on that shouldnt.
Having the meter in the circuit will allow you to turn off, disconnect or check specific circuits.
REMEMBER!!!!!! Each time you wake up the BCM, you will have to wait till it goes back to sleep to get an accurate reading.
My 02 ZO6 never has a dead battery and a couple monts ago, outof no where, battery was dead.
Something stayed on that shouldnt. After I charged the battery, all was back to normal.
Accomplish the following:
Do the current draw test and see where your at.
Fully charge the battery and go have it fully tested to rule the healt of the battery out as a possible problem.
Bill
Without that data, your shooting in the dark. Put a DC Current tester/meter in series with the NEGATIVE BATTERY terminal/battery cable and see what the BCM Sleep Current Draw is after the BCM goes to sleep (approx 5-12 min)
It should be right around 20 milliamps (0.02 amps) If its High,, something is staying on that shouldnt.
Having the meter in the circuit will allow you to turn off, disconnect or check specific circuits.
REMEMBER!!!!!! Each time you wake up the BCM, you will have to wait till it goes back to sleep to get an accurate reading.
My 02 ZO6 never has a dead battery and a couple monts ago, outof no where, battery was dead.
Something stayed on that shouldnt. After I charged the battery, all was back to normal.
Accomplish the following:
Do the current draw test and see where your at.
Fully charge the battery and go have it fully tested to rule the healt of the battery out as a possible problem.
Bill
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
WHEW!
The BCM is one of those modules that dont have the inputs /outputs on one page. 
They are spread out over numerous sections.
What specific pinouts do you need to figure out?
Power/ground ??
Column Lock??
Lighting??
PCM/BCM interface??
DLC stuff??
Something else??
The BCM is one of those modules that dont have the inputs /outputs on one page. They are spread out over numerous sections.What specific pinouts do you need to figure out?
Power/ground ??
Column Lock??
Lighting??
PCM/BCM interface??
DLC stuff??
Something else??
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
WHEW! The BCM is one of those modules that dont have the inputs /outputs on one page. They are spread out over numerous sections.
What specific pinouts do you need to figure out?
Power/ground ??
Column Lock??
Lighting??
PCM/BCM interface??
DLC stuff??
Something else??
The BCM is one of those modules that dont have the inputs /outputs on one page. They are spread out over numerous sections.What specific pinouts do you need to figure out?
Power/ground ??
Column Lock??
Lighting??
PCM/BCM interface??
DLC stuff??
Something else??
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
ahh yes, thanks for digging that up
You can leave it connected or not. The guy from Compliance Parts (Rich?) that I talked to suggested disconnecting it. I see why now. It appears that it will always have power, so yeah like you said if it gets hung up it'll pull your battery down. But as I suspected, none of the leads that the LMC5 overrides will have power when the ignition is off.
My CLR went bad and that is what prompted me to get the LMC5.
The Column Lock Relay, which does NOT exist in the 97 -98 model years, but is installed for all other model year C5's, appears to be left connected. So if the BCM grounding of the CLR were to get hung up for some reason, the CLR would be powered all the time and could quickly drain the battery. Although I have not checked other wiring diagrams to see what else might be powered by fuse 23, fuse #23 in the passenger footwell could be removed and prevent the battery being drained. Alternatively the CLR could be pulled from the socket and the same results achieved.
My CLR went bad and that is what prompted me to get the LMC5.