Parasitic Draw - 99 V8 SHO

[SHObogdan1]

Hi everyone, I have a parasitic draw on my 99 SHO. I tested the draw by hooking up a multimeter to the negative battery post and to the negative terminal to measure amps. It had about 1 amp draw. I pulled one fuse after the other and measured current each time. I found one fuse that made the current drop to 0, and that was Fuse 1- Battery Junction Block. After pulling out each fuse in the interior fuse panel the reading did not change. One thing I found out though, when I hooked up the multimeter, there was a constant clicking noise coming from the battery saver relay. I finally pulled that out and the ticking stopped but the current draw didn't change. Maybe this happened because the GEM module didn't enter sleep mode yet. I think the relay might be bad, but not sure. Can it be something more serious? Could the GEM module cause the excessive current draw in my case?

 

[98SF19]

codes?

Any DTCs? P06##? Are you on the original football radio/AC (EATC)? That's a common source of current draw, though I don't think 1 amp is very bad. Depends on the state of your alt. and how long car sits between use. Check heatsink behind EATC after a few hours (at which point GEM will be in sleep mode).

Some info on GEM from the explorer forum:
http://www.explorerforum.com/forums/showthread.php?p=1725290

 

[SHObogdan1]

The check engine light has been on for about a month and I scanned it with a code reader and code P1413 shows up (Secondary air pump). I haven't looked into that since it is emissions related. The parasitic draw has been going on for about 3 or 4 years now. Before 2008, the car was driven everyday so the battery didn't have time to die out. After that, it has been driven less and that's when I realized it has an excessive draw. This car had a strange electrical problem ever since I bought it back in 2000. Occasionally the windshield wipers would turn on randomly (without turning the wiper switch). It wouldn't happen all the time, sometimes when starting the car. I don't know it this contributes to the amp draw or not, but I pulled every single interior and exterior fuse/relay and the amp draw did not go away. Not even the wiper fuse or radio fuse made a difference. I tested the alternator and voltage stays constant at 14.4 volts or so.

 

[SHObogdan1]

Any more tips? Is the battery saver relay supposed to click constantly when hooking up a test light from battery negative to the negative terminal?

 

[SHOZ123]

I would guess you are not waiting long enough for the various modules to go to sleep when checking so the readings are not good.

Obviously pulling the main fuse will stop the draw and then there should be a secondary circuit that is still pulling the amps when the main fuse is back in.

One amp is too high, normal draw is under a 1/2 amp when everything has settled down.

What I did is connect my meter and have it in a location where you can read it with the door closed. Then look at it after 15 minutes to see what your parasitic draw is. Then open the door and take out the interior light fuse and start looking for the mysterious draw.

I bet it's the football.

 

[stephen newberg]

Its almost always the football. Particularly if it is still the original one. Eventually something dies in there and if you get a refurbished one, the problem is gone and does not come back. I never did get from the Ford people I know any info on what was the cause and what they fixed, but you can often tell a refurbished one by a very minor burn/flash imprint to the lower left of the front facing of the football that you can just see through the faceplate.

pax, smn

 

[SHObogdan1]

I re-did the parasitic draw test, but the fuse in my multimeter blew and I can't measure dc amps anymore. So I used a test light, unhooked the negative side of the battery cable and pulled fuses out a day later. I found that fuse 17 under the hood (rear control unit/cd changer) is contributing to the draw. When the fuse is plugged in, the test light glows very bright. When I disconnect the rear control unit fuse, the light becomes extremely dim and flashes slightly, it barely stays lit but doesn't completely go out. However, if I pull that fuse out and fuse 1 (fuse junction panel) the light completely goes away. I'm not sure how to accurately test the interior fuses without the GEM module coming on. On most other cars, you can just clamp the door ajar switch which will trick the GEM module into thinking the door is closed. Any way to do this on the 99 SHO?