# 2000 Cavalier Battery drain on cluster circuit



## Eagle152 (Sep 2, 2011)

Greetings, 

I have a 2000 Cavalier that is a battery killer.
The previous owner told me after the fact that if I just turned off the radio before turning off the car, everything would be ok.

I have replaced the door switch and put in a new battery. Then I checked for a draw on the battery. It goes from 800 mamps to 72 after about 15 seconds. Let the fuse pulling begin!! On the cluster fuse it went from around 600 mAmps to 2 after 15 seconds. The cluster has a digital odometer that was looking strange and cleared up if I pushed on the cover so I changed it to a different one (looks good now). Still have the draw on the circuit.

I cannot find what the normal draw is on a Cavalier but everything I read says that anything over 30 to 50 mAmps is too much.

Any assistance would be greatly appreciated - I am tired of pulling the cluster fuse everytime I park for more than 15 minutes.


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## octaneman (May 13, 2009)

Hi Eagle152


Is there a molex connector to the cluster or it a ribbon? Did you inspect the connector for any pins that maybe shorting out ? Do a voltage drop to ground test on cluster harness pins , to do this test you connect the black lead to the ground pin connector and the other to the chassis. Turn the ignition and crank your engine ( 2 seconds), the meter should read 0 or near zero, if you get battery voltage then its a short on the ground side. Do the the same thing on the positive side but the only difference is the molex connector is on the cluster and one lead of your meter is to the positive pin and the other to the positive of the cluster. Turn the ignition on crank the engine (2 seconds) if you get battery voltage there is a short on the positive side. 


Note: Inspect the cluster for any shorted out light bulbs, dimmer/light switch and do the voltage drop test on all the positives and negatives on the cluster trace's to isolate the short. 

post back your findings.


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## Eagle152 (Sep 2, 2011)

Thanks for the response - It is a molex connector and I will diagnose it this weekend and let you know what I find.

I did notice that the dome light is off until I put the fuse back in. Not sure if this is because of the control module or what because the dome light itself is on another circuit (near as I can tell).

By the way - what is an ecceptable mAmp drain?


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## octaneman (May 13, 2009)

The limit is set by the manufacturer but the rule of thumb on wires and switches is in volts because you're doing the voltage drop test. 

Battery cable length up to 3 feet 0.1v 
Battery cable over 3 feet 0.2v 
Magnetic switches 0.3v 
Solenoid switches 0.2v 
Mechanical switches 0.1v
Battery cable connectors 0.05
Connections 0.0v 

Use these readings _only_ as reference _not_ as absolute values, for that you need the manufacturers specs. 

Checking for short using the amp scale is roughly 150mA, again you need manufacturers specs. When testing the amp draw (parasitic drain) _on the whole vehicle on the positive side_ which means connecting one probe of your meter to the positive post of the battery and the other lead to the positive battery terminal. _*Do not crank the engine you do so at your own peril. The reading must not exceed 10 amps or you will destroy your meter completely*_. I cannot stress this enough, your meter must have the capacity to take the load with a minimum 10 amp fuse. 



post back your findings.


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## Eagle152 (Sep 2, 2011)

Greetings 
I tried what was suggested to test the cluster, I didn't see any problems with it. I did replace the cluster to get a better readout on the odometer.

Is there anythin else on the circuit. I have a haynes but do not see what else it could be.

Thanks for your suggestions.

Patrick:4-dontkno


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## octaneman (May 13, 2009)

Is the cluster digital or analog ? I can't recall per se if the cavaliers had digital clusters so you're going to have to help me out here. In an analog cluster there are step motors that drive the indicators like the RPM gage or speedometer. These step motors fail from time to time causing a minute drain on the battery, the drain is gradual and consistent it eventually kills the battery. Digital clusters have fiber optics traces that light up when a small current is applied that is run from a microprocessor to a driver I.C.
Is there a PCB with I.C's on it ? Does it get hot ? If it does look for any cold solder joints around the board and re-solder them. 
If you can post a picture of the back side of the cluster it would help considerably with the diagnostic. 


Question: Is the parasitic drain on the positive or negative side of the battery ?


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## Eagle152 (Sep 2, 2011)

The drain can be seen on both positive and negative sides of the battery.

Eagle152


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## octaneman (May 13, 2009)

A current draw that large can come from two places, either the starter or the alternator. Look at the main positive cable from the alternator to the battery, make sure there isn't an exposed connection to any other wires along the harness. Do the same thing on the starter side but inspect the wire going to the solenoid. Start to isolate the main draw by disconnecting the starter and alternator and then do your current draw test with either your test light or DVOM by connecting them back to power one at a time. Double check the cable terminals and that no fusible links are shorting to ground to the fuse/relay box. 


_*Important Note*_: *The computer has to be in shut down mode to accurately perform the current draw test. The computer's shut down mode will take approx. 5 to 10 min to completely dissipate any excess current within its circuits. Connect a test light in series to disconnected positive terminal, turn ignition on (engine off doors closed) the test lights intensity should diminish to zero as the current slowly drains from the system. 


*
post back your findings.


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