Need help guys.I disconnected my negative battery cable and connected a test light to cable and motor and light comes on.I assume I have a draw some where but cant find it .I pulled one fuse at time and light stayed on.Any suggestions.

 

If I am reading that description correctly, your providing a ground with the test light.

A test light isnt the best way to locate a drain

 

You need to use a vom set to ma to find the drain. Using the correct tool works, and disconnect/remove the door lite fuse also.
Best for you to use the search function, advanced, archives to find the process, its been said a hundred times over on the forum...search and ye shall find

 

Thanks for the replies .I have been trying to also use vom meter but I'm not to good with it .Vinnie you say use the ma setting what should I be looking for with this setting .I removed each fuse one at a time and I used the volt meter and it showed 12 volt drain.

 

There are a bunch of pieces in our cars that will cause a draw on the battery.

Some are REAL loads, some are not.

Examples:

The 'memory' for your station presets in your radio. The interior lights. The underhood lights. The volitile memory in the computer. Etc., etc.

Heck, it could even be a draw from the diode pack in the alternator.

I suppose the very best way to locate the culprits would be to disconnect them one at a time but you'll STILL have some draw. It's just the way it is.

If the battery won't stand the 'normal' draw from the 'normal' stuff then the battery has an issue I suspect.

Hth,

Jim

 

You likely have a VOM (voltmeter, ohmeter, milliammeter) test meter. Read your manual to set up the meter to measure current. You measure current by placing the meter in series with the load. Remove the negative cable from the battery, set the meter up for measuring current and connect the meter probes, one on the neg cable and the other on the neg batt terminal. The meter must be initially set to measure at least 10 amps because the courtesy lights are going to come on. If you set the meter for say, 400 milliamps full scale, you will pin the meter and either damage the meter or blow out its internal fuse if it has one. Best to pull the courtesy light fuse first, then set the meter for full scale approx 400 ma. depending on what meter you have. GM says leakage current should not be more than 50 milliamps, my 87 draws 27 ma. . Watch the meter while you pull one fuse at a time and if current drops dramatically, you have determined what circuit needs further investigation. You didn't say what year C4 you have, so I cannot offer further info other than if you have the jump start bolt behind the battery, remove the nut and disconnect each of the 8 wires one at a time while watching the meter.
Before you measure current, you might want to wait until it is dark and look at the underhood lights, vanity mirror lights, center console light, door panel map lights. Don't leave your key in the ignition parked because this keeps the anti-theft circuit on. Do you have a radar detector, aftermarket alarm, radio, audio amplifier? Check em. After the battery has been connected for say an hour, feel the seat adjust motors as several posters have found defective adj motor switches that kept the motors on and stalled.

 

JFB I have an 85 vette I leave the keys in the ignition most of the time .So I took them out to see what happens over night. I will try your suggestions tomorrow and see if I can find the draw I dont have power seats wished that was the problem.I checked in the dark for lights on but no such luck.Thanks /Steve

 

Just went through this and what I did was pull all the fuses to the things I did not need anymore....not sure if this is an option for you, but it solved my problem.....checked it the last few days and the battery reads 12.7

Be sure to check the current draw the proper way - otherwise you will blow the fuses in your digital volt meter....ask me how I know.

Hence the reason I just pulled the fuses I no longer used like the ECM and injectors etc....and a few others.....keep checking you will find the one,..then the fun starts trying to find the problem...

 

jfb: you know, each time you write this, must have been 100 times since i've joined the forum, i know that its appreciated... Why not write a tech tip and have the mods post in the C4 Tech tips,,, would be great reference for all who need help in the electrical diag area... I for one have used it several times....thanks, vinnie