Carburetor fan possibly drains battery below 12v - ever happen to anyone else?

tvmaster

True Classic
Okay, here’s what’s up so far. Overnight, with nothing attached, battery went from 12.75v to 12.51v.

Used Dan’s method, with BOTH a digital and analog meter. Couldn’t get the ‘G’ light to illuminate. Wiggled wire, etc. no go. BUT, when doing this and observing both meters, voltage dropped down into the 11.6v range.

Any idea why? I assumed I’d see the same voltage reading taken off the battery terminals.

I’m certain the bulb I put in was working - tested it with a 9v battery before inserting into the cluster.
 

Jefco

High Mileage
Check the connections at the 'lump', if the light circuit goes thru there, it's a likely place for an open circuit.
 

tvmaster

True Classic
Check the connections at the 'lump', if the light circuit goes thru there, it's a likely place for an open circuit.
Is there any way that shorting something on the alternator (I.e. causing a spark by touching the wrong things together) could kill the internal regulator, killing the circuit to the bulb?
And there’s still the mystery as to why the alternator isn’t charging over 12.07v
 
Is there any way that shorting something on the alternator (I.e. causing a spark by touching the wrong things together) could kill the internal regulator, killing the circuit to the bulb?
And there’s still the mystery as to why the alternator isn’t charging over 12.07v
Certainly, bad things could happen if you shorted the alternator output to ground. I don't think you could kill the bulb circuit with 12V across it since that is what it sees with the key on and engine not running. Fix the light issue first. It is not just a light. It provides current to excite the field windings. Then, I recommend you download the installation instructions for that model alternator and check the connections.
 

tvmaster

True Classic
Certainly, bad things could happen if you shorted the alternator output to ground. I don't think you could kill the bulb circuit with 12V across it since that is what it sees with the key on and engine not running. Fix the light issue first. It is not just a light. It provides current to excite the field windings. Then, I recommend you download the installation instructions for that model alternator and check the connections.
I have an appointment with the seller/installer tomorrow or Tuesday, but in the meantime, when you said "put 12v across it", what exactly did you mean and how would one do so? I'm trying to learn stuff before I take it in :) Taking the small wire and connecting it to positive meter connection, with negative to ground point, did not illuminate the magic lantern.
 
Find the wire that goes to the bulb from the alternator. The original was connected to the D+ terminal on the regulator according to the schematic. Grounding that end of the wire with the ignition switch on should light the bulb if all is well since the other end of the bulb is connected to 12V.
 

Dan Sarandrea (Phila)

Waitin' On Parts...
Okay, here’s what’s up so far. Overnight, with nothing attached, battery went from 12.75v to 12.51v.

Used Dan’s method, with BOTH a digital and analog meter. Couldn’t get the ‘G’ light to illuminate. Wiggled wire, etc. no go. BUT, when doing this and observing both meters, voltage dropped down into the 11.6v range.

Any idea why? I assumed I’d see the same voltage reading taken off the battery terminals.

I’m certain the bulb I put in was working - tested it with a 9v battery before inserting into the cluster.
There's always a bit of a slip between cup and lip.....meaning whatever the multimeter shows when directly connected to the batt + and - posts will always be more than what you are going to read downstream on any circuit, due to resistance/age/corrosion/loose connections/etc.

The trick is to lose as little as possible.

As someone else posted, if you put the d+ wire (the one at the alt with the red plastic terminal connector) to ground with key in run but engine off, it should light the lamp (to use a hockey term :) ).

Let's get that, and then go from there.
 

tvmaster

True Classic
Find the wire that goes to the bulb from the alternator. The original was connected to the D+ terminal on the regulator according to the schematic. Grounding that end of the wire with the ignition switch on should light the bulb if all is well since the other end of the bulb is connected to 12V.
Not sure how old Mr. Fiat guy rerouted from the D+ terminal, but the Nero/Viola appears to be the wire which used to go to the external regulator then on to the bulb, if I read the flattened, color schematic correctly. By grounding, unattach from the regulator and attach to clean frame, yes?
 
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tvmaster

True Classic
There's always a bit of a slip between cup and lip.....meaning whatever the multimeter shows when directly connected to the batt + and - posts will always be more than what you are going to read downstream on any circuit, due to resistance/age/corrosion/loose connections/etc.

The trick is to lose as little as possible.

As someone else posted, if you put the d+ wire (the one at the alt with the red plastic terminal connector) to ground with key in run but engine off, it should light the lamp (to use a hockey term :) ).

Let's get that, and then go from there.
Light the lamp? Well then, it doesn’t play for the Leafs during a playoff run….
 
Not sure what the D+ terminal is, but the Nero/Viola appears to be the wire which used to go to the external regulator then on to the bulb, if I read the flattened, color schematic correctly. By grounding, unattach from the regulator and attach to clean frame, yes?
Yes
 

tvmaster

True Classic
For that matter, if I was suspicious of a wiring fault somewhere along the line, could I connect a ground wire directly into the C7 connector feeding the cluster? that should effectively do the same thing, but bypassing all the vehicles wiring coming from the engine bay, yes?

UPDATE: Success on lighting the lamp. Ground to Blanco/Viola did the trick. Ok, where does that get us - broken wire or broken regulator/alternator….
 
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ng_randolph

Bjorn H
For that matter, if I was suspicious of a wiring fault somewhere along the line, could I connect a ground wire directly into the C7 connector feeding the cluster? that should effectively do the same thing, but bypassing all the vehicles wiring coming from the engine bay, yes?
No, that would not do the same thing. The D+ terminal on the alternator needs to be connected to the lamp in the dash. This is essential for the alternator work. The suspicion is that you have a break in the wire between the lamp and the D+ terminal on the alternator. The first thing you need to do is to verify this, e.g. by (as has been suggested a few times) unplugging the red connector from the D+ terminal on the alternator, and then grounding said red connector with the ignition on. Let us know if this turns on the light in the dash.
 

tvmaster

True Classic
No, that would not do the same thing. The D+ terminal on the alternator needs to be connected to the lamp in the dash. This is essential for the alternator work. The suspicion is that you have a break in the wire between the lamp and the D+ terminal on the alternator. The first thing you need to do is to verify this, e.g. by (as has been suggested a few times) unplugging the red connector from the D+ terminal on the alternator, and then grounding said red connector with the ignition on. Let us know if this turns on the light in the dash.
See post #91. Grounding Blanco/Viola (now removed from the alternator’s connector) to frame produces ‘G’ light.
 

Jefco

High Mileage
May be a silly catch-up question, but is your engine grounding strap (from the transmission to the body shell) intact and well attached to clean metal?
 

tvmaster

True Classic
Now make sure it is connected correctly to the alternator. I would check the installation instructions.
Both cables seem firmly attached. They are attached where the expert installed them. I can't get up in there to see well enough, but are there fuses that can blow inside the regulators?
 
Both cables seem firmly attached. They are attached where the expert installed them. I can't get up in there to see well enough, but are there fuses that can blow inside the regulators?
I doubt it is fused, and I'd be surprised if you blew it up. If it is wired correctly and does not work, it was likely bad from the start if it could not keep the battery charged. You should really get those instructions in case there is something subtle that has been missed.
 

tvmaster

True Classic
I doubt it is fused, and I'd be surprised if you blew it up. If it is wired correctly and does not work, it was likely bad from the start if it could not keep the battery charged. You should really get those instructions in case there is something subtle that has been missed.
yes, that's a fine idea if I could actually see the model number, lol. I know, I know - jackstands. they're coming :) He told me it was a 61amp Bosch - can't imagine there are that many models from the era which just slid right on an Exxe.

Funny how this started as a carb blower that wouldn't turn itself off, and now it's progressed to this. Somehow, it's all inter-related. A year ago this weekend is when we shot the WD episode ending. Where has the time gone....
 

ng_randolph

Bjorn H
See post #91. Grounding Blanco/Viola (now removed from the alternator’s connector) to frame produces ‘G’ light.
Good information. Now, if you reconnect the red connector to the D+ terminal on the alternator, does the "G" light turn on when you turn on the ignition? If you tug gently on the PRP/WHT wire, move it around a bit etc, does the light flicker / turn off / turn on?

Do you own a test light? Something like this? Note that this is the kind that does not use a battery (the type with a battery looks similar, but is usually called a continuity tester). If you do, unplug the red connector from the D+ terminal on the alternator. Clip the alligator clip on the test light to the fat B+ output on the back of the alternator, and touch the tip of the tester to the D+ terminal on the alternator. The test light should light up, and if it does not you can be quite certain the voltage regulator has gone bad.
 
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