Hey guys i have an 85 f150 5.0 automatic 2wd, the battery has a serious draw will die completely over night. I have done the parasitic draw test and narrowed it down to the BLK/O wire from the solenoid. it draws 4.8 amps if i disconnect the voltage reg it drops to 2.66 If i disconnect the ALT, IGN, HL switch no change? i took apart the splice and re soldered it cause its old but i am out of ideas. i know the BLK/o wire is a fusible link with a shunt in it but seems like the yellow wires adjoined to it are the culprit but from everything i see they just go to the ign, hl switch but cant find the Y/lg tiny wire route.


Any help would be greatly appreciated

 

I'd say the rectifier diodes in your alternator are toast.

 

The BK/O wire also feeds the fuse box (fuses 12 - pwr door locks, 4, 8 - light switch, dome, 16 -horn,speed control, cigar lighter). You should be able to pull these fuses to see if the draw drops to zero.

 

i went through and pulled all the fuses but no change at all in the amp draw that was the first thing i did in hopes it was a circuit in the block. The alt is new which doesnt exactly mean much, but with the alt completely disconnected doesnt change anything either.

 

I've cured a similar issue in two separate cases one with the headlight switch and one with the wiper switch both drawing to ground in the off position.

 

ill go check the wiper switch but i unplugged the headlight switch and no change, the only change i got was from the volt meter plugged in pulled 4.66 and removed i got down to 2.66 i have pulled dome light bulbs under dash bulbs, everything i can think of the 4 wire plug that is by the battery with the 2 yellows wires i tried but its so tight i dont wanna yank the wires out of the socket i may cut the wires and see if that changes anything then reconnect them but i unhooked everything that the large yellow wire goes too but i didnt unhook the ammeter yet to try

 

You can't be 4.xx or 2.xx volts in a 12V system.
Are you sure you are not set to amps?

Disconnect all the leads from the battery+ stud of the solenoid.
Set the meter to amps and connect one lead to the positive battery cable.
Touch the other lead to each of the wires in turn and note which ones have a reading, and how much it is.

Let us know exactly what you find.

 

If u read the 1st post u will see its all in amps and no where did I say the readings were volts I said volt meter but nothing about volts

 

I do read
You need to learn to speak.
It is NOT a voltmeter.
You are using the ammeter of a digital multimeter!

Good luck with your battery drain

 

U are correct it is a multimeter but in all my posts states amps as well as which wires effect it

 

Look at the starter solenoid large terminal that goes to the battery +. There are smaller wires there that feed the whole truck.

Set your ammeter up between the negative cable and the negative of the battery. Leave it there while you are doing your testing. Get your 4.8 amp draw.

Then go over to the solenoid and pull the small wires off the solenoid bat + side. The drain should go away. Those wires feed the whole truck. If the drain does not go away, look for other things added to the battery + like amplifiers and trailer brake controllers.

You seem to already know the wiring a little bit over there, so if the drain goes away when you pull the small wires off, then put them back on till you find the one that is the culprit. Then go on down the line finding out when it goes away and when it comes back.

 

not to be an *** but in the first post i stated the BLK/O wire off the solenoid is the culprit but its not the alternator from that wire it splices to a big yellow and small Y/LG wire which feed the hl switch ign switch ammeter this is where my issue is but with that disconnecting all of the above there is no change as in post #6 with a DVOM, MULTIMETER, AMPMETER connected i have tested all of these as well as all the fuses in the truck. i know my way around electrical and am very familiar with testing for parasitic draw but the BLK/O wire has a shunt in it as well as a fusible link for the ammeter in the dash n alternator but with all these things disconnected and no change is where i am baffled

 

Check the wires coming off both plugs to your alternator.
My old 2G alternator on my 1986 F150 had completely melted the both big black (B+) wires as well as the yellow wire (A) from the 3 pin plug. These trucks are bad for doing that.

 

If you pull all the wires off the battery and still have a draw, I suspect your meter is not right.

You know your way around wiring, I believe you, just stop and think about it for awhile and get your thoughts together. What scale do you have the meter on? You will always get a draw on these trucks, but it's going to be more like .048 amps.

You might want to try this simpler method.

 

no i got all that the ONLY WIRE that has draw testing the way EVERYONE says which is how i have done it for YEARS is the only way to test draw with ALL the wires connected EXCEPT the BLK/O wire i have 0amp DRAW, the BLK/O wire has a splice out of that splice is the BIG YELLOW wire that feeds the IGN and HL switch and someone said the wiper switch as well but i havent been able to confirm that. just down from the solenoid on the BLK/O wire there is a rubber (cant think of what you call it) splice with 2 more wires out of it so out of the BLK/O wire there is 4 wires and i can only find what the Big YELLOW and the SMALL Y/LG ( that goes to the ammeter on the dash) there is nothing else that i can find to test draw unless i start cutting wires or find a schematic. (I HAVE TESTED EVERYTHING FOR DRAW BY DISCONNECTING THE NEG. BATTERY TERMINAL AND PUTTING THE RED AND BLACK LEADS ONE TO THE BATTERY AND ONE TO THE TERMINAL WITH MY METER SET TO DC AMP) i appreciate the fact everyone is triin to help but i have already done everything stated in all of these posts WAY BEFORE i posted. i have been a mechanic and done electrical for 16 yrs but this ford is killing me cause i cant find a schematic with the BLK with ORANGE trace wire with 4 wires coming off of it any where and ithe 4 wires are that way from the factory.