DALLAS916

1966 GT convertible, 75,000 original miles, totally rotisserie restored 2004-2008. All new or NOS components. Has about 700 total miles on restoration. Charging and all instrument circuits worked fine for 6+ years. Last 2 have been problematic.

I have a current drain of approx. .7 amps. It started by killing two batteries over 2 years, then caused some glitches in my Rally Pac and now an inoperative ammeter. I have tested the fuses by pulling all of them and reading the draw on those circuits. NADA. Tried reading draw off solenoid connections. NADA. Have not tried the alternator connections or regulator connections. It has been suggested I could have a diode bleeding. The charging system works well, pushing over 14V back into my battery, but unless I disconnect the battery + the drain will take it all the way down (I don't drive or start it very often). I'd like to NOT have to remove the number/date coded alternator to have it bench tested at some facility or shop.

IS THERE A WAY FOR ME TO TEST THE ALTERNATOR AND/OR REGULATOR CIRCUITS FOR CURRENT DRAIN WITH THEM BOTH ON THE CAR. IN MY GARAGE. WITH TYPICAL MULTI-METER. YOU GET THE IDEA.

imp

Of course! But first, how do you know the drain is 0.7 amp? With the engine shut down, key OFF, the alternator to battery main feed wire must have no current flow through it. If there is, it's going backwards, from the battery, through at least one bad diode, to ground. Connect a DC ammeter in the battery + connection, that is, remove the + battery terminal (cable), connect an ammeter between the cable terminal and the battery post: if current is flowing, BAD ALTERNATOR. imp

PotteryPal

DALLAS916

No tilt-away. I don't believe '66 had them. I posted an album, though.

DALLAS916

Already did a general current draw test with good ammeter. Draw was .696 Amps. Tested all fuse circuits and those at the solenoid. No change in amps. I'll go back and test at the alternator wires/connections.

08'MustangDude

You use the AMP Meter between the - battery terminal, and the - battery cable, with the
car off, keys out of the ignition.


THEN you pull fuses to see when the AMP load either goes down, or disappears.
Then you pull the + lead off the Alternator, check for same results.

DALLAS916

Right....been doing this. We've probed the alternator, even removed it and had it bench tested. It's fine. What we did find, though is perplexing. The BLACK-YELLOW wire from the solenoid + is still showing a .68A current draw. The YELLOW wire coming from the solenoid also pulls a .68A draw, probably because they are spliced together, even after pulling the connection to the regulator. So, the alternator and regulator are out of the loop and cannot be the draw. SO, IS MY NEXT MORE TO GO INSIDE THE CABIN WHERE THE BLACK-YELLOW AND YELLOW LEAD? I'll try removing all the fuses again. That would leave the LIGHT SWITCH and the IGNITION SWITCH to cause the draw. Tomorrow is another day.

Gun Jam

.68 is a lot of current. if a standard car battery can supply 60 Amp hrs that means if a load of 60A was applied it would be dead in 1 hr. in this case a load of 0.68Ah is being applied that battery would be totally dead in 88Hrs or 3.5 days.

.68A is enough to make heat.

Things that would use .68A would include: Lights like map / roof, and trunk lights, dash and glove box. are any of these running? check at night. Radio / cd head units, Amps, Sub woolfer, GPS Trackers, or any other goofy aftermarket crap. Fuel pumps, fans things of this nature???

Ignition systems and stock things others than lights typically wont draw that much current...

does any of this ring a bell or give you any ideas?

bop11

DO you have a single wire alternator? If yes probably a bad diode. If no, either a bad diode or the mechanical regulator is not opening the field circuit when the engine is off. Lift the alternator wire off the starter solenoid. battery side post and see if the draw goes to 0. If yes the alt or regulator are suspect. If no then you have a short or bad component, however removing all of the fuses and still having a draw sort of points to the alternator.

DALLAS916

I have removed the alternator (a 3 wire harness) completely to have it bench tested, which it passed 100%. With the alt out of the system, the draw is still there. I pulled the connection to the regulator, and still have the same .68A draw from the black-yellow wire set that goes from the Solenoid to the firewall, and powers many of the lights and other components. The headlight switch and the ignition switch get their power BEFORE the fuse block. IE, you can turn on the headlights without the key on, and obviously the ignition switch has direct power. WHAT I NEED NOW IS TO TRACE THE BLACK-YELLOW AT THE FIREWALL CONNECTION AND INTO THE FUSE BLOCK again. I will try pulling all those fuses, but there are lots of other components that are not fused because they have separate breakers or little metal-cased fuses. I do have an aftermarket radio, but seldom use it. The clock on the Rally Pac stopped working after 6+ years keeping perfect time, and the tachometer will only rotate to about 2500-3000 rpms. Both are routed into the fuse block if I remember, but could be wrong. I know adding the Rally Pac and ammeter changes the harness and connections at the solenoid, but it has all worked perfectly until a year or two ago. SOMETHING on that black-yellow powered circuit is drawing current. Finding it is being a bitch. OH...DOES THAT 8 PIN CONNECTION AT THE FIREWALL (THE ONE DOWN UNDER THE DRIVER SIDE HOOD HINGE) COME APART, OR DOES IT DISCONNECT ON THE INSIDE OF THE CABIN PAST THE FIREWALL? It's very tight, but the whole connection moves around a lot when I pull on it. The schematic shows it is a pinned connection with two halves, but it sure feels like it doesn't want to come apart.