500ma draw from where...

[ah1988ford]

Does anyone know anything on a truck that pulls 500ma ???
I took the negative lead off of the left battery and put my multimeter in "parallel" one lead on the battery post and the other on the negative cable and got .5amps. Where do I start I am lost when it comes to electrical stuff......
If let the truck sit for a couple of days the batteries have little or no juice left.
Do I just pull fuses until the draw goes away ?
When I tested this i had the doors shut and no key in the ignition, I also removed the light bulb from under the hood, so I think I got a pretty good reading.

 

[dgr]

A 6 watt something. Sorry, I couldn't resist.

Pull the wires of your alternator to see if there is a draw there. Then you've got it -- pull fuses. Hopefully between the two you can isolate where the draw is coming from.

 

[racer30]

Do you have a modern cd player? The tuner/clock/memory will draw some power when off. its usually a yellow wire from behind the stereo.

 

[ah1988ford]

Dont have a newer cd player yet ...lol
I do have a fairly new alt it is a powermaster, one of the ones where you have to rev to 1500rpms to "excite" the charge to get it to pump amprage.
The alt is internally regulated, and the ol external voltage regulator from the previous alternator is unplugged ..... wonder of my problem may be there.

 

[jwalterus]

even the factory radio with the clock draws to keep time and channel settings

 

[Wyreth]

your stereo will draw that, try pulling its fuse and see what you get then.
is your glovebox or ashtray light stuck on?

 

[jwalterus]

another item to note, if your underhood light works, it'll draw too

 

[Ruger_556]

Does anyone know anything on a truck that pulls 500ma ???
I took the negative lead off of the left battery and put my multimeter in "parallel" one lead on the battery post and the other on the negative cable and got .5amps. Where do I start I am lost when it comes to electrical stuff......
If let the truck sit for a couple of days the batteries have little or no juice left.
Do I just pull fuses until the draw goes away ?
When I tested this i had the doors shut and no key in the ignition, I also removed the light bulb from under the hood, so I think I got a pretty good reading.

If you have an amp clamp you can just follow the current up from the battery without breaking into the circuit anywhere. Otherwise pull fuses and unplug stuff.

 

[NO_SPRK]

12v car phone charger?

 

[franklin2]

500ma is too much as you already know. Even with all these new fangled cd players and other stuff, your draw should not be over .070 or 70ma. Like someone else said, keep your meter on there, and start pulling wires off the alternator and start pulling fuses. When you find it, the draw will stop or go way down.

 

[icanfixall]

Let the truck sit overnite and feel the alternater in the morning. If its warm to the touch thats the probelm. The alternater diode bridge is shorting out. What this means is the diodes cause the circut to open when you shut off the engine. If just one of the diodes in the bridge stays closed it will continue to think the alternater is making power and try to push it to the battery. But noting is being made so the drain is backwards into the alternater. An alternater needs to spin to make power. When it stops no power is made so there has to be a way to open the circut so the battery power is not sucked back to ground thru the alternater. Thats the job of the bridge. An alternater has two jobs. One the engine is started it refills the used power in the batteries. Then it runs every piece of electrical equiptment on the car or truck. So if you have a huge stero or amp or lots of lites your going to need a bigger alternater. No way are the alternaters designed yo recharge a dead battery. Yes they will do just that but its a lot of work asking them to do that. Also a long cranking to start causes more battery drain and wears out the starter so please fix the reason for a long crank.. Or end up replacing many starters and we know thats not a fun long with the top hidden bolt. I read somewhere here that some members don't use the top hidden starter mounting bolt... Pleas... Do not do that either. What your doing is deceaseing the bolting power by 33%... Thats not good anywhere.