When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
A good first place to start:
-Does the car have any mods that connect into electrical? Aftermarket stuff and installs tend to have a higher failure rate than OEM.
-What changed from when it was ok to when it started having this issue? Did it go in for repairs, have a function fail, etc etc.
Assuming you want to troubleshoot this yourself, do you have a multimeter? You need to measure current draw for the whole system (which should show an out of spec value) and then step down sub system by sub system to figure out exactly which circuit is drawing the majority of that current.
Once you identify the circuit, then you need to identify the component on the circuit (which varies in complexity as different circuits have varying levels of complexity / accessibility).
1ST OF ALL... THANK YOU SO MUCH FOR RESPONDING!! I LIVE ON A MOUNTAIN & DONT HAVE ANY OPTIONS REALLY, MUCH LESS SOMEONE WHO ACTUALLY KNOWS WHAT THEIR TALKING ABOUT ("Everybody's a mechanic," lol.)
When I bought my 'dream car,' I was told it "can be a bit hard to start in the cold." I'm pretty sure this issue started at the beginning of winter a cpl yrs ago, shortly after I got it. I haven't drove it but maybe 20 times total, though I would at least fire it up a few times a week. Then this issue started, almost from the get.
Stereo is am. Have read the (15 amp?) is a common problem with similar issue.
No function fail prior, but now a/c & heater no longer come on.
Have access to a multi meter, but I do not know the procedure (not stupid just very new, but definitely ready; I catch on fairly quick!)
The person who built it is a "reputable long-time GM Mechanic" (fwiw) however getting ahold of him has proved to be unsuccessful.)
I'm pretty sure this issue started at the beginning of winter a cpl yrs ago, shortly after I got it.
OK, probably no leads there then. I was just checking to see if maybe it just popped up recently after something was serviced/ replaced.
I haven't drove it but maybe 20 times total, though I would at least fire it up a few times a week.
Maybe a long shot, but is it possible youre not putting back in as much energy as you're taking out with that method? Starting a car, especially in the cold, takes a lot of power. If all you did was start it and idle for a minute (for example), its possible that the alternator hasn't made enough energy to replace what was consumed by the starter, especially since they tend to not charge as well at idle.
No function fail prior, but now a/c & heater no longer come on.
That's a tough one. I was hoping for a failure that coincided with timing on the draw issue. Is the whole HVAC panel dead or is it getting power?
Have access to a multi meter, but I do not know the procedure (not stupid just very new, but definitely ready; I catch on fairly quick!)
There are probably some good existing guides on YouTube for multimeter parasitic current draw tests. Its not complicated, but it would take a good bit of text to properly explain and I'd bet there is an existing video that does a better job explaining than I could.
The short of it is switching the multimeter to amperage mode and hooking it inline with the circuit youre trying to test.
At the start of the process, youre looking at the whole system (so positive battery cable off hooked back up flowing through the meter). You do have to be careful that the car is off / everything is off as the capacity of the meter to test like this is low - several circuits on will blow the fuse in the meter.
That tells you total system draw that can be compared to commonly accepted 'normal' values. If its excessive, then you start going system by system to measure draw from each. One of the easiest starting points is the fuse box. You take a fuse out and reconnect the circuit through the meter. With the car off, the vast majority will be dead 0. But you should eventually find the circuit or circuits that have measurable draw that makes up the total system draw you measured earlier. Component level test varies by what circuit it is.
The person who built it is a "reputable long-time GM Mechanic" (fwiw) however getting ahold of him has proved to be unsuccessful.)
What do you mean by 'built it'? What did he do to it? I'm not trying to knock him, but I'd be suspect of aftermarket changes before investigating OEM issues.
If this is a daily driver, meaning you don't have the luxury of time, you'll need to take it to someone who knows what they're doing. I would think there are folks on this forum who are within a hundred miles of you who either know how to diagnose this or know of a reputable place where you could take the car.
If time is on your side then you can follow a laborious process of elimination to locate and isolate the cause of the drain; mind you, my expertise is with 2nd gen and earlier but the principles should still apply.
Set your multi meter on high end of the AMP scale. With the engine NOT running, connect one lead to the pos (+) on the battery and the other lead to the alternator output. It "should" normally read nearly zero. Move the AMP scale one step lower then check the reading. Repeat until you get a noticeable reading. You see, so as not to blow out your meter, you start at the highest setting then move on to the more sensitive setting until you see a change in the reading. If your meter is digital, when you see a definite change in reading, note what it is then reverse the leads and check the reading again; it should be about the same only with a change in sign (+ vs -).
Now comes the laborious part.
With the battery disconnected at the ground, remove all the fuses from the fuse box.
Reconnect the battery and the meter then note the reading on the meter; it should be zero. If you're getting a reading at this point, you may have an issue in your alternator.
If your initial reading is zero, reinstall a mission critical fuse, like for the ignition, then note the meter reading. Repeat this until you see a big change in your reading. The big change is likely a problematic circuit. Note that circuit, pull that fuse, then continue checking circuits; you may have more than one problem circuit.
With the problem circuit(s) identified, find the problem/cause within that(those) circuit(s) and correct accordingly.
Monte Of The Month -- May 2015 Monte Of The Month -- March 2017
Join Date: May 2013
Location: Nebraska
Posts: 5,285
This is a long shot but a friend of mine had an 03 Monte Carlo and it had a draw on it that sometimes would give him fits during a drive. So hat he finally found out was there was a wire in the rear back of the engine that was landing on the exhaust pipe and causing this to happen.
This could be a similar issue if it was rebuilt and something didn't get attached correctly. Check the diagram for the rear of the 3800 motor and see then if anything might be different under and back there.
Most likely there is a broken wire that shorts to a metal component some place this could have happened when the engine was installed or something was remounted on the wrecked car.
This is the rear of the engine and the Red arrow is pointing to the power steering pump for reference, the 02 sensor is right behind the exhaust port flange This diagram gives the location for the items in the location of the engine.
11-02-2021, 02:22 PM
Lady needs help!!
