ECM battery drain
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
The ECM IS drawing power from your battery, but it shouldn't be a problem starting, with a healthy battery after no less than a month. Check the amperage draw. I think your FSM says there should be no more than a 50 ma draw. If there is, start pulling fuses and disconnecting circuits until you find the draw. Be sure to either pull the courtesy light fuse or let them time out before making tests.
RACE ON!!!
RACE ON!!!
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The ECM does indeed include a computer chip and many circuit components in the ECM have 12v applied all the time, but a good ECM draws very little current and with the ignition off, the computer chip in the ECM is not running. I seriously doubt your ECM is drawing enough current to discharge your battery that you can determine.........BUT, it is possible. You can prove its the ECM by measuring the battery leakage current after the courtesy lights time out, ign off, and then remove the ECM and measure the leakage current again.
Racer
Joined: Oct 2007
Posts: 250
Likes: 1
Hello,
I had a mysterious drain and found it to be one of my underhood lights. They use a gravity switch to turn them on/off. My right one was sticking. I noticed it when I turned the lights off in my shop and saw a little 'glow' under the car (not really bright). I raised the hood and felt the glass lenses. The left was cool and the right was just warm (not a lot of heat from those little bulbs). I removed the bulb and problem solved. Something worth checking.
After the fact, Friends told me about problems with the little gravity switches. Worth checking.
You All Take Care and Be Safe, -John
I had a mysterious drain and found it to be one of my underhood lights. They use a gravity switch to turn them on/off. My right one was sticking. I noticed it when I turned the lights off in my shop and saw a little 'glow' under the car (not really bright). I raised the hood and felt the glass lenses. The left was cool and the right was just warm (not a lot of heat from those little bulbs). I removed the bulb and problem solved. Something worth checking.
After the fact, Friends told me about problems with the little gravity switches. Worth checking.
You All Take Care and Be Safe, -John
Le Mans Master
Joined: Jul 2007
Posts: 5,356
Likes: 2
From: No HOA, New Hampshire
Cruise-In X Veteran
St. Jude Donor '09
Hello,
I had a mysterious drain and found it to be one of my underhood lights. They use a gravity switch to turn them on/off. My right one was sticking. I noticed it when I turned the lights off in my shop and saw a little 'glow' under the car (not really bright). I raised the hood and felt the glass lenses. The left was cool and the right was just warm (not a lot of heat from those little bulbs). I removed the bulb and problem solved. Something worth checking.
After the fact, Friends told me about problems with the little gravity switches. Worth checking.
You All Take Care and Be Safe, -John
I had a mysterious drain and found it to be one of my underhood lights. They use a gravity switch to turn them on/off. My right one was sticking. I noticed it when I turned the lights off in my shop and saw a little 'glow' under the car (not really bright). I raised the hood and felt the glass lenses. The left was cool and the right was just warm (not a lot of heat from those little bulbs). I removed the bulb and problem solved. Something worth checking.
After the fact, Friends told me about problems with the little gravity switches. Worth checking.
You All Take Care and Be Safe, -John
Glove box light in my Blazer
Thread Starter
Instructor
Joined: Apr 2007
Posts: 215
Likes: 1
Thanks for the replys guys. I know i don't have any lights on anywhere, I am now looking into the horn relay as my horn doesn't work. Maybe the relay is stuck. I just picked up a relay and the 2 horns. I will install them on Sunday and retest my drain.
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