Depends on the engine wire harness - how the three are wired. One would have to look at a diagram.

The electrical system is a parallel connected system. Think of a ladder.
Each ladder rung is a circuit - alternator, battery, and loads.
The sides of the ladder are power buses - big conductors of power.

With alternator off, battery supplies power to the loads.
Alternator running, alt supplies power to the loads and can be monitored by voltage. Alt must supply over 15% of battery voltage to recharge battery.
Battery charge lead usually has a fusible link for overload protection - two wire sizes smaller than service wire. It could be the red lead from BATT stud is tied to the fusebox stud - same electrical point as battery pos post.

Harbor Freight usually has sales and one can pick up a jumpbox for $40 for not only a dead battery, but also to keep the vehicle's PCM, BCM, radio alive - no security code to enter.

 

this car is a 98 body but a 2000 engine, ecu, transmission. i had to repin the gauge cluster to get that to work and did some rewiring on the passenger side kick panel to get things to perform the way they are supposed to. i think i remember reading something about how the red alternator wire on the engine harness is supposed to go to the gauge cluster, but i remember not needing to use that one due to the voltage being part of the serial data wire that many of the gauges run off of. do you think this could have something to do with it?

edit: i forgot to thank you for your help. this will get ironed out eventually.. im pretty persistent and i love this car so we'll get it figured out. thank you so much for your input, its really appreciated.

 

You're welcome. Remember, the stupid question is the one not asked.
Gauge cluster? OE or add-on?
How is add-on connected to electrical system?

 

ok so im still having this issue and ive picked back up trying to take care of it. this will be my last attempt before taking it to a shop.

So ive been toying with a few things trying to figure this out..

Im using a third different TRUCK(from a denali/escalade), 145 amp, NEW(not rebuilt) alternator. It still whines with ignition off. Ive put a new excitor wire on, still persists. New battery, but Ive tried 2 different batteries in total.

I was playing with the multimeter the other day with the excitor wire and tested the voltage. Somehow, on DC voltage I was able to see 1.65V from the excitor, and on AC setting 02.7. Like.. does that make any sense at all?

Also, with all the fuses plugged in, battery plugged in, alternator plugged in all properly.. I pulled some of the relays/fuses and noticed that both the 50A ignition fuse AND the big ignition relay(next to the starter relay), caused the sound to go away from the alternator when the whining is present. I tried replacing both the relay and the fuse with new ones but it seems that did not help because the sound returns when I start the car then shut it back off.

Could this be an ignition problem? What do you think would be the best course of action here? Maybe ignition switch? Thanks again guys.

 

I picked up a second new multimeter today just to verify that mine was working correctly. I did the regular draw test.

Hooking the meter in line with the negative cable produces 0.157-0.158 amps. Is that 157 milliamps or 15.7 milliamps? Well.. I went under the assumption that it was 157 milliamps making it 130 or so over the standard. I disconnected EVERY F'ing THING in the car lol. When I say EVERYTHING, I mean.. if I could get to it.. its disconnected right now. Every fuse, every relay, every plug inside the car including completely disconnecting the radio, bcm, ecu, alternator. Everything that I could possibly reach.. and it didnt change the reading one bit except for minor fluctuations between 0.148-0.160 amps that didnt seem to have any rhyme or reason and I am to assume that these fluctuations might have just been the connectors on the terminal and the negative cable wiggling as I moved around the car testing everything.

In fact, between both multimeters(different brands), the readings were identical at 0.158 amps. I know I was on the amp setting because it has microamps(uA), milliamps(mA), and regular amps(A), and on the mA setting it said "OL" meaning overload Im assuming.

How could I possibly have that kind of draw with nothing in the car plugged in? Im so confused.. lol.

Edit: Oh and I must have missed your post so long ago Everett. My gauge cluster is OE but is one from a 99 car since I did the swap and was repinned by myself with the help of GaryDoug kind of guiding me on the basic principles of things. Once I repinned that, the car ran great aside from this continual issue that has been present for as long as I have had the car. That said, the cluster itself is OE but I replaced the faceplate on it with one of those glow gauge ones. It has a connector at the bottom of it that connects to an inverter that has two wires: black(ground) that I have connected to a ground in the underdash wiring and the red one I run to the ACC slot in the interior fuse panel. I installed it but have had it disconnected ever since then because I havent wanted anything else to potentially drain the battery. Basically, its there but I dont use it until I get this all figured out.

 

While watching ammeter, was/is alternator unplugged and red wire on BATT stud taken off?
Never mind, earlier post stated alt unplugged.
VATS module?

 

OK alt unplugged showed 0.009 but with it plugged in, no change.

 

Okay, I would not worry about 9 milliamps.
This amp draw tells me the red wire on alt BATT stud is still attached.
At the drvr kick panel, is the body harness plug and this connector removes the rear lights, fuel pump/tank, etc.

 

Ok.. so what your saying is that the alternator is good but something else has to be the culprit and you are thinking maybe i should try the stuff in the driver side kick panel? Ill do them here this morning and get back to you.

I dont know if this is worth mentioning but since its an electrical issue.. maybe theres some correlation. Ok so my main driver(my 93) had an alt failure and yesterday I had to take my 98 to get a replacement. After doing the draw test the day prior to yesterday, I had left many things disconnected so I had to plug all that back in to be able to go. I was having a no start issue that turned out to be my gauges fuse in the interior. I discovered it was blown, making it so the fuel pump primed but there were no lights on the cluster and no crank at all. I popped in a new one and it started up. Then while going to get the part for my other car, the fuse blew again 5 mins down the road. I stopped to get money and 3 more blew right as I plugged them in before I realized that my cluster overlay was plugged in but still blowing the fuse despite the inverter being connected by ground wire with the positive wire disconnected. So I disconnected the inverter entirely and the fuse has not blown since. This is the first time Ive ever encountered this issue and I wonder if you think maybe this is related in any way?

The cluster is a stock 99 v8 cluster with a white glow gauge overlay that has a connector coming off the bottom to an inverter. I have the inverter ground wire connected to one of the metal supports for the steering column, and the positive connected to the empty ACC slot in the interior fuse panel. I have had the positive disconnected but left the ground connected because I figured it would be inert like that. Am I wrong in thinking this or could the inverter still be affecting the electronic systems in the car?

Anyways, thanks for your continued help and Ill be back shortly with the amp draw test suggestions you made.

 

Sorry I did not read the whole post, As I skimmed through it the thing that I noticed is you are saying is you are chasing .158 amp draw that kills a battery in 5 hours?

If so the math does not work. Your issue should be well over a 1.00 amp draw to take down a new battery in 5 hours. .158 amps would be an issue if you said the battery dies after a week of sitting. To put that in perspective 75-100 miliamps is the grey area if it worth investigating. I wonder if your draw requires a certain condition to be met before the real problem is shown. One car I did came from another shop that the mechanic gave up on. He started by pulling the fuse for the interior lights so he could do the tests with the door open. He tested the rest of the car top to bottom then gave up. The issue was in the interior lights. Lighters that short "sometimes", glove box lights that come on for days after hitting a bump and under hood lights are the first things that come to mind.

I would try to find a low current inductive amp meter. It will show the problem better. Sometimes the inline amp meters themselves can make the issue stop just because of their resistance.