Does anyone know how much current the car should draw with everything off at rest. I have a drain (or the battery is going bad) and I will start to run down where it is, but I need to know what current the car SHOULD lose while in the parked and off position.

Looking for a number in milliAmps. If you don't know perhaps someone with a stock Series III without a parasitic drain, might put a voltmeter in line with the battery and let me know how much current is drawing?
I've done this once before (run down a parasitic drain) and knowing this number beforehand is really useful before pulling fuses.

 

On older cars like ours, without a slew of control modules n' stuff, 25 milliAmps is a good rule of thumb

Cheers
DD

 

Hi Doug

So I chased the electric gremlin this morning. I hooked up my multimeter and measured and got 1.95 mA which I think is 195 milliAmps. Actually, I'm never sure how to read the damn thing but I think it was 195 mA. I put a test light in line and it glowed bright orange with everything shut off. Started pulling fuses and the light went out when I got to the trip computer's fuse in the driver's side under dash fuse box. I took and kept that fuse out. I tested the draw again with the multimeter and I got 1.09 mA which I think is still very high. On the other hand. The test light stays off in the current configuration.

So, my question now is whether I am just reading the multimeter wrong since DOug has sayss sleep draw should be 25 and I am at over 4 times that even with the fuse removed and the test light dark.

 

It is just me., Confused on the new process....

Carl

 

So I'm checking for parasitic drain.

1) Turned everything off. Place multimeter with switch placed on mA between neg post and neg cable (in other words... in series).
2) Reading is 1.96 mA. This is probably because I set the multimeter switch incorrectly. I think this means 196 mA.
3) To confirm reading, I removed multimeter and replaced it with a test lamp.
4) Remember everything is off. Test lamp in series between negative post and negative cable light up.\
5) This means parasitic drain is confirmed.
6) Start pulling fuses. Test lamp stays lit until I get to trip computer fuse in D/S under dash fuse box.
7) When that fuse is pulled, test light goes out.
8) Replace test light with multimeter with settings as above. New reading is 1.10-1.15 variable.
9) Replace multimeter with test light to re-confirm. Test light stays off.

I believe this means I have isolated my parasitic drain to the trip computer because test light is totally dark. Not even dim. But I am concerned by the 1.10-1.15 mA reading.

I am asking for comment on this seeming disparity.

 

remove the radio fuse too.

 

I have several multi-meters and I, too, sometimes get the readings bollixed up....as different meters have different range settings, "auto-ranging" (which will catch you off-guard), etc. Some have a "Range Hold" function is helpful.

I think you're correct in thinking you had 196 mA and reduced it to about 110 mA. Now keep pulling fuses and see if it drops more. There might not be even current flow to make the test light glow.

Don't forget to unplug the alternator as well, if pulling more fuses doesn't drop the reading

Cheers
DD

 

Sorry to hijack the thread but I am smashing my head against the wall with a '84 XJ6 draw from the alternator. Doug, would you know where I could find a picture of how the back of the alternator is wired. It is the Lucas style (not Bosch). The wiring in the car has two brown wires (original ends are long gone), and the Brown/Green indicator bulb wire. I have a 4 amp draw with the replacement alternator. My concern is that there are two threaded lugs on the back of the alternator and one should not be used. The car got to me with a 3 amp draw and as soon as I removed the wires going to the alternator at the left bulkhead power post, the draw was gone. Replaced the alternator and draw is back with a vengeance. Any help is appreciated. All my shop info, including the Jaguar Repair Manual with diagram don't clearly show this version alternator. The replacement number is Bosch AL397X and multiple pictures on an internet show the backside. Any help is appreciated.
Mark