Does anyone know what an appropriate amperage draw should be when the car is off (not running)? It's a 1999 VDP. I am measuring .41 amps. The battery is less than 2 years but obviously not brand new. I had a dead battery tonight after work and nothing was left on. I jumped it and it started easy and drove fine on the way home. Any thoughts?

Thanks in advance for any suggestions.

Larry

 

The discussion on the forum indicates that 30ma is the 'sleep' current draw. That is 0.030a, a little more than you describe. Leaving the key in the ignition keeps the car from going into sleep mode and another few issues have surfaced that keeps the security system 'alert'. One, a turn signal switch if I remember correctly was covered by a Technical Service Bulletin (TSB). Look through this list or use the search function. https://www.jaguarforums.com/forum/g...r-index-50609/

With your 0.41a the security system would be the first suspect. Pulling fuses is the next step.

 

I figured it was too high of a draw - thanks for confirming that. Looks like Saturday I will be pulling some fuses. I'll start with the security system. I'll post when resolved and Thanks!!!

 

I found a minor draw that .41 amp draw in half, still leaving a parasitic draw of a .20 amps. This is higher than the 30 ma draw that is supposed to be there. since cutting the parasitic draw in about half, the battery has started the car, even in the -15 F weather we have been having. For now, I am going to run it and see what happens. Thanks again for the input!

 

But what was drawing the power?
How did you fix it?
.
.
.

 

The draw that was discovered was from a aftermarket install of a satellite radio receiver. Since I am not using it, I just disconnected it.

 

The "horizontal" switch in the ignition switch assembly has ben mentioned as a possible culprit. It detects the key being in the barrell. I have not personally experienced this.

 

That is an interesting thought. I have had some problems during the cold weather where I pull the key, but the ignition barrel sticks and it is though the key is still in. Working the key in and out does resolve this and it is easily noticed because the steering wheel does not retract.

I have pulled each fuse twice with an assistant watching the current draw and could not eliminate the remaining parasitic draw; I think this must mean that the parasitic draw is in an unfused circuit. The only unfused circuits I can think of are through the alternator or possibly the starter. I have read about diode failures in the alternator that can lead to parasitic draw. The weather has been incredibly cold and I have not yet checked for this.

 

Suspect that ignition switch.

 

I have pulled all fuses and relays looking for the circuit where the parasitic drain could be originating and didn't find it. How do I test the ignition switch other than what I have already done? Thanks for any ideas.

 

All the fuses??? In the four boxes?

 

Yes, all of the fuses and relays (twice). There are 2 fuse boxes under the hood, 2 under the back seat (left and right), and 1 in the trunk for a total of 5 fuse boxes. I also checked with 2 different amp meters just make sure it was not an instrument problem. Other than the alternator diode theory, I am out of ideas. Thanks!

 

I think you'll have to disassemble to get at it and probably replace it.

 

Hmmh. Did you remove the fuses one at a time, or did you progressively remove them so that no fuse was left in by the end of the process? The reason I ask is that some modules receive power from several sources and it is possible that either source could supply current under some strange and unusual circumstance.

Other than that, the other unfused connections seem to be the alternator, as you mentioned, and the "auxiliary positive relays" located at four of the five fuse panels, but they seem to be a hardwired circuit to the ignition switch. It might be worth unplugging them. In addition to the diode leakage, the alternator regulator circuit would also seem to be unfused. Unhooking the alternator power and regulator leads would isolate that. Too bad it is in such a bitch of a location.

Good luck.. Please report back, since you are certainly not the only person who have been down this road. Some have even put a high power switch in the battery lead to power down the car when unused, but that is wrong on so many levels.

 

I did remove one fuse at a time and check the draw and then replace the fuse. When removing certain fuses and then replacing them, the draw would first jump up to about .75a amps and then after a short time drop down and stabilize to around .25 amps; I believe this was related to electrical items shutting down or timing out. I also pulled every relay in every fuse box as well as the relays located outside the fuse box area. I have to wait until we get some warmer weather before I attempt the alternator. You are right, the location of the alternator does not make things any easier. Thanks for the ideas.