Parasitic drain hunt?

BRIANJAG2000

MEMBER
2000 JAGUAR S-TYPE
4.0L
V8
2WD
AUTOMATIC
150 MILES

Having electric issues, the alternator failed and toasted battery at the same time. Ordered an alternator and got a new battery on warranty. Upon installing the new battery so I could use my locks while I wait for alternator (no alternator in car) I noticed the battery was drained the next morning so I did a parasitic drain test and come to find out that f18 fuse (passenger fuse compartment) radio/navigation/cell was pulling 3.5amps and f20 (same compartment) was pulling 1amp GEM/air conditioner/instrument cluster power. With those 2 fuses removed my drain is.40ma. I thought it might be my amp, so I unplugged it and tested it again, not the amp. Do you guys have circuit information for those fuses? I've gone as far as I can and could use some help. Thanks

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Hi,

If removing those fuses stops the draw, the problem is after the fuse. I looked at the power distribution schematic and located the fuses.

If you look below, I attached the schematic showing what those fuses power. I would disconnect one component at a time to see which stops the draw.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pic below.

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Friday, March 10th, 2023 AT 10:32 PM

BRIANJAG2000

MEMBER
8 POSTS

Thank you very much, that's exactly what I'm looking for. Two more questions - (1) say I'm looking at F18 20amp fuse, I follow the diagram down to navigation display module FC67 (how do I find the module itself). This is the part I really would like to learn, comprehension of the diagrams. Is there a key you can send me, so I know what these symbols and numbers mean? Is there a place where all these modules are located? I will be hunting for this problem module today and also installing the new alternator. Thank you, Joe.

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Saturday, March 11th, 2023 AT 4:18 AM

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Hi,

Without a manual, it will be difficult to locate the components. However, I can help so don't worry about asking.

If you look at pic 1 below, it shows the display module. If you open the trunk, it is on the left side.

The remaining pics provide the other information you requested.

Let me know if this helps.

Joe

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