QuestionQUESTION: Rowland- I'm trying to help out my mother-in-law with her 2006 Chrysler T&C mini van. She is having a problem with the battery going dead and it not starting. The battery is not very old and I have one of those carbon-pile battery testers and it checks out OK. I also cleaned all battery connections. Finally I pulled the negitive cable and put a digital ampmeter between the cable and the negative post and found there is a 1.1A draw with everything shut-off. I then started pulling fuses and circuit breakers in the under hood fuse & relay center and found when I pulled the hazard/turn 20A fuse, the draw dropped to 0.21A. If memory serves me, a long time ago I was told that 0.6A was the max draw on a battery, anything over that an if a vehicle sits for more than a day, the battery can go flat. So, I'm assuming there is an issue in the turn/tail/hazard circuit. Now, I know that electrical problems take time and circut tracing to figure the problem out and I don't have the time to do that for my mother-in-law due to my work schedule. So, what I want to ask of you is are there any "know" or "common" issues in this circut that I could check for possible quick fixes? Oh, yeah, this van is equipped with the power sliding doors and rear hatch that when in operation, the hazard flash. Thank you for any information you can offer me.
ANSWER: Hi Keith,
If the fuse you speak of is #14 at the front of the box, then that indeed is the ignition off draw fuse whose purpose is to power everything that is needed when the ignition is nonetheless off. Here are the possible items:
dvd/cd changer, hands off module
radio
sentry key immobilizer module
auto temp control for AC/heater
body computer (supplies power for the hazards/turns,interior lights)
overhead console
adjustable pedal switch
horn relay
park lamp relay
wiper relay
I wonder if a hidden light such as the glove box or underhood might be on. Other than that you could try removing the relays and plugs to those device which are easily accessible one at a time to see if you can drop the current draw of course with #14 in place.
Please let me know if you find the cause.
Roland
---------- FOLLOW-UP ----------
QUESTION: Roland- Thanks for getting back with me on this so quickly. No, it is not the draw-off fuse. The fuse I am refering to is labled "HAZ/FLAS" on the relay center. It is located towards the battery between two of the larger relays. Sorry, I would have gotten the fuse number for you last night, but could not make it over to my mother-in-laws to do so. Otherwise, I like your thinking on the possible " hidden light on" theory. let me know what you come up with. Thanks- Keith
ANSWER: Hi Keith,
Then that is fuse #24 and it powers one segment (hazard function) of the body computer (pin #2 of plug #1), and part of the instrument cluster (gauges and warning lights). I don't think it powers the turn/tail signals. You can try to figure out which by going under the dash on the left side (remove under panel silencer and knee blocker) and that will give you a good view of the body computer which has 4 plugs on its bottom. Plug 1 is the smallest of the four plugs and only 3 or 4 wires in use. Adjacent to the body computer also on the left side is a rectangular large disconnect with approximately 76 wires, and when you open that it will disconnect the fuse output wire that goes to the instrument cluster. So see which of those causes the current through fuse 24 to drop as you have measured. I don't show the details of the hazard function of the body computer but it obviously does power the hazard lights off of that fuse. Let me know what you find and perhaps we can narrow this further. The ignition off draw should be about 25 mA with no lights on, and all timed out systems off (which might take about 15 minutes). Even when you fix the #24 problem there appears to still be excess IOD.
Roland
---------- FOLLOW-UP ----------
QUESTION: Rowland- I finally was able to get my mother-in-law's schedule and mine together this past week-end. I set up my amp meter and disconnected the 76-pin connector; nothing, same draw. I then unplugged the 4-wire connector on the body computer and the draw dropped to 0A. I reconnected the 4-wire back into the body computer and the draw was back. Do you have any direction as to what I could check next to determine what through the body computer is causing the draw?
AnswerHi Keith,
We know that there is too much draw on fuse 24 (hazards) which supplies pin 2 on the 6-pin/4-wire plug at the pcm. So we have to figure out why that is the case.
We also need to find another current draw related to the bcm to know how to get this down to around 25 mA. But there are 3 other current supplies to the BCM:
Unplugging C1 as you did disconnects the draw on fuse 24 (hazard), and also disconnects the draw on fuse 19 at pin 5, a non-specific current supply to the bcm. I would suggest that you see what the resistance to ground is shown at both pin 2 and pin 5 of that socket of the bcm. Or even better see what happens to the overall current draw at the battery when you remove fuse 19 and then remove fuse 24.
Then on bcm plug C2 (34-pin black/green) pin 5 draws current from the ignition switch but only when the key is in the run/start so that is not a problem with the battery draw down.
Pin 7 of C2 draws on fuse 14 (IOD,powers all system that are needed when the ignition is off) so either see that that pin' resistance to ground is on the socket-side or better see what the overall current draw is when you remove fuse 14.
So basically: Let us see how much of the overdraw is being sucked individually through fuses 14, 19 and 24 from the battery when the ignition is off.
Roland
