Some of you may rememebr this problem. I started a similar thread to this a few months ago and thought I had the problem fixed, but I guess not.

Here is the story. Wife is demanding a new car and the budget will not allow it, though explaining this to her is not possible.

Her 2004 v10 with 151,000 miles sometimes will not start once in a while. This has been going on for a few months. Every once in a while the truck will be totally dead or the battery will be very low. Carrying a booster pack for jumping seems like a great idea to me, but not to her.

18 months ago got a new alternator.
2 months ago replaced the battery and the wiring harness for the pos and neg terminals

So today would not start, the battery was low - clicking only.

So I jumped it, drove it around for a while, made a couple stops, and all was well.

When I got home I turned off the radio, A/C, lights, adn let her sit for 20 minutes.

Then checked the voltage:



Then disconnected the neg terminal and checked if there is a drain:


if you can not see, the black lead is in the COM port, the red in the other and the voltmeter is set to mA DC



Are these readings OK? What is the next step?

Please, I am slow - so be specific

Thanks,

Greg

 

the voltage regulator is bad in the alternator. I had this problem with a windstar and it was the alternator. disconnect the altenator wire and see if your voltage draw stops

 

...Now with everything reconnected, start the engine (if you could). Test the voltage at idle and remember it. Should be about 13.8 to 14V. Now, have someone rev it up to 2000 RPM. Your voltage should be right about the same. It should not fluctuate way up or way down.

This is how you can check the voltage regulator also.

 

OK guys keep the help coming. I reconnected the battery and checked the voltage - it says 12.39:



then started the truck and let it idle (about 1000rpms):



then had my beautiful, tired, and complaining 16 year old daughter rev to 2000rpm's:



What next? Do I need a new alternator?

 

put your meter back on mA and do that same test again. just disconnect the alternator and see if your current draw changes

 

Sorry, but I need more specifics.

Put on mA - I can do that, but what do I connect the leads to? The pos and negative terminals or between the negative terminal and the ground wire? And if I do that how do I start the thing? And disconnect which wire on the alternator?

Sorry for so many questions, but I am slow.

 

After further contemplation I think I know what you mean. I set the meter to mA DC

I disconnected this:



and this:



and applied the meter thusly:



and got this:



What next?

 

I think CrzHelm is saying with the engine off, disconnect the big wire on the alternator. Then again disconnect the negative wire off the battery. Connect the red lead of the meter to the bare negative post on the battery, and black lead of the meter to the loose black negative wire you just removed and see what the current is.

 

Wait - I think I found the drain - sort of...

After and internet search I changed the red wire on the multimeter to the 10A side and then checked b/n the negative terminal and the cable and found that it read -1.6A.

I also heard the DVD player go on when I put the multimeter in place. Is there a fuse for the DVD player only or just the entire radio?

 

OK - this is getting nuts - so stay with me.

When I put the multimeter in b/n the terminal and the cable I got -1.6A and I heard whixxing on the inside. went inside the truck to check it out and it was the cd player and the dvd player. I removed all the cd's and the dvd and rechecked with the multimeter.

Now I am down to -.55A

Am I doing better or just confusing myself?

 

I think you may have found what's draining your battery. Is that DVD/CD player a Ford OEM unit or was it aftermarket? Who installed it if it is aftermarket?

That -1.6 A will be 1.6 A if you reverse the probes. Put the red probe on the battery post instead.

 

You are on a good track now. I was wondering where you were going with the Vdc ma. readings. youre using meter right now . Be careful most meters when set up to read amps has 10 amp fuse inside if you exceed that it will blow then you might run down wrong road again if do not know that fuse has blown.any way enough on the meter. back to cd player. It is very common for audio equipment,ecu's and electrical devices to go through a self test or reboot when power has been disconnected and reconnected I would connect your meter in line again with everything switched of and monitor amp draw if its at near 2 amps again and you can hear the the player functioning give it about two min. and see if draw drop down. I also had and excursion and found if i let sit for over a week the battery would be low. these trucks propably caryr a .5 amp draw normal. that should not run battery down overnoght or propably even few days. I usually do not like to see over .2 of amp draw. .If that checks out ok and still having problems. you need to fully charge battery . Then let sit or remove surface charge. then test voltage and cca. you will find lots of batteries will test good cca but carry low voltage. I stay away from them. A fully charge battery should be 12.7 volts + or - .1 if below 12.6 not fully charged. or bad battery. Whenever you buy a nw battery always make them load test it before take it. you wont believe how many batteries are bad on shelf. I work at dealer and have had as many as three failed batteries in row before got good one. any ways first see what voltage is if it is not 12.5 or above scrap it. same thing with your battery if you charge it and the battery will not hold good voltage range you will always have trouble out of it. and second load test battery with quality tester.now if battery is good and no excessive load on system when sittting. test charging system. very common problem I run into is the charging cables are not sufficient to supply amperage rating of alternator output to batteries. The vehicle may charge enough to run but not mainain ood battery life. you can quickly check voltage at output terminal of alternator and then at battery terminal. you should very little drop if any if proper sized cable is used. Or even better if have high dollar load test . oad test the cable v.drop and see what amperage it will carry. I have found that on most trucks with 90 amp alternator it wil take a 1 ga wire to carry 100 amps at a distance of about 6 feet. I know lots of automotive is running 60-100 amp alternator with little bitty wire like 6 ga. This just doesnt cut it. Any way ive rambled enough. I'm sure someone will correct me with exact specs or scientific differences. I am telling you from my everyday experience what I know. good luck.

 

OK - it is morning and I am refreshed and a little more knowledgible - but I still suck at spelling.

So I decided to start the whol process over. And start with the basics.

So when I got up this AM I went to Sams to return the core for the old battery which I bought on Sept 22. That means it has been 6 weeks since I have had any issues with the truck. While there I asked them to check and load test the battery.

The report siad battery is good. 12.7 volts, holds a charge, and the charging system is good.

So now to the next step. Let the car rest for 30 minutes. And then check for a drain.

Greg

 

when you do the mA test like you did before try to not disconnect the battery terminal completely with out first getting your meter connected to the 2 terminals. if you let the power get interupted then it will cycle some of the vehicles electronics when power comes back on causing your faulty readings. so put your probes on both the battery and the terminal then disconnect.

 

yeah, I figured that out the hard way.

So here is the daily update.

When I first connect it, it reas -1.6A draw. After a few minutes - when it cycles thorugh everything it goes to -.55. If I repeat later it goes to -.21.

So I figure I have a 21-55mA draw is that correct?

That seems normal so I am leaning toward an intermittant short.

So how do I track that down?

Does this make sense? Wife is breathing down my neck for a new truck and I think the Ex will last forever. She doesn't like my idea of just carrying around the portable jumper with her.