I have the same problem with my 2006 silverado Z71.
I detest GM products but this one got me what I wanted and at an affordable price. So here I am.
In my case we don’t drive it very often and it’s one of those vehicles that has so much drain from “always on” electronics that our solution is to just drive it at least once a week. Otherwise it dies.
Windshield leak (common problem). Water drips down and shorts the GEM module. Drains battery.
Good luck reaching the GEM module. Mine finally dried out by itself and went back to normal.
As I said before, put the test light between the battery and the disconnected battery terminal- this will act as your amp meter- dim light is normal and a bright light shows a draw. Pull fuses one at a time.
But the battery should measure 13.8 volts when not running connected or loose from battery cables, 13v or less means the battery is failing.
Auto parts stores here will test the battery free why don't you try that...
Around 20 years ago my Sister gave me a 91 Crown Vic. It was in nice shape but a few things didn’t work. The only one which was important was the water temp gauge didn’t work.
I drove it for a few months and realized I really needed that gauge to work.
One day a guy was visiting. I had done him a favor so it was a good time to ask him if he could tell me what was wrong with the gauge.
Well he opened the hood, touched something and told me the temperature sender was bad. It did not take him more than 5 seconds. He showed me where it was and said it was cheap and easy to replace. Sure enough it was.
It sure was nice to have a meter working.
Just mentioned this because it is surprising what a guy can do who knows what he is doing.
Remove the cigarette lighter.
Did ja git that darn thing fixed yet???
Ok, later in the thread you posted that the battery is new and the alternator is new...sounds like there has been a hit or miss approach to chasing down the problem?
Let me ask - is the vehicle driven every day...and still the battery is going dead? If this is true, there is likely a charging problem. Which, in my experience, can usually be traced to a corroded negative battery cable/connection.
Well, as a long-time Ford engineer, I could solve that problem in a minute - except for your gratuitous slurs against my employer for lo these many years!
The first thing to do....would be never assume it’s a battery drain.
I hope you are able to resolve the issue easily.
Best of luck- have a great evening.
Could be worse...it could be a Tesla.
Push it to a dry area...
Break Switch sticking causing the break lights to stay on after exiting the vehicle?
Modern cars and trucks have a parasitic power drain - various on board components constantly draw power even if the car/truck isn’t running.
Get a battery charger to maintain the battery and always keep it hooked up at home.
Fords tend to have odd electrical and computer problems as they age and tend to be tricky to track down. Unlike GM products that loose wheels or the fuel pump goes out leaving you suddenly stranded. GM issues tend to be kind of obvious (and sometimes dangerous).
I’d see about an auto electrical specialist. We have one nearby but if it is wet where you are it would probably be a long drive - we haven’t had rain in weeks.
I can think of more creepy things to worry about than a make of car....
You may be dealing with leakage from the battery cables. Try replacing them.
Is there an aftermarket trailer hitch with a connector for the trailer lights? Could be a partial short there. A dead short would likely blow a fuse. A switch or a light not turning off completely would cause a slow drain. Any light left on would be easy enough to find, and a stuck lighter would probably burn up before it drained the battery. I agree with the suggestion of reading the battery voltage across the terminals with the engine running. Any less than 13 volts is not charging the battery. Since it and the alternator are new, I’d start looking at the regulator.
If it’s a 98 F-150, I had the same issue. I think it was water splash issue - water would splash up and get something wet which kept drawing power after the truck was shut off. My solution was to install a kill switch on the battery, so when it was wet I would disconnect the battery while the truck was parked. Didn’t fix the problem but it worked around it.
Not sure if I understand what you are doing here.
Does this mean you have the positive and negative terminals connected to the battery and your meter setup is Black meter lead on Neg. terminal of battery and red meter lead on Negative cable where it meets engine ground??? That would read -12.76 Volts if your ground connection was open (bad ground cable or connection at battery or engine connection).
I had this problem on a ford many years ago where the culprit was the short red cable from Battery to starter solenoid on fire wall. Car acted like the battery couldn't start car but when I put the meter across that cable I measured 9 volts when trying to crank the car over.Only 3-4 volts was getting to Starter.That short cable was bad
Is battery really draining down or are the symptoms a no crank condition?
Need several more points of info to really help
But I will give ya a few things to try.
If the battery is really being drained, Then the Ammeter/testlight in series with power cable and pulling fuses will help you find which circuit is causing the drain. Then trace wires looking for shorts or rub marks.
If the symptom is a no crank condition even though there is a new battery, Then you may have bad connection/cable in the ground or starter cable.
Starter circuit uses heavy duty wires because the starter pulls huge amounts of current when engine cranks and any resistance in line will cause a voltage drop and the starter won't get the voltage/amperage it needs to crank the engine.Circuit path is Positive battery terminal thru large red cable to starter motor, thru starter case to engine ground and back to battery thru Black cable.
You can put volt meter across each section of circuit and look for voltage drops.
1.) Meter across battery terminals,try to start truck. If voltage drops way down and stays down while trying to crank, Battery isn't doing it's job.
2.)Meter from Pos battery terminal to starter connection. try to start truck.If you see a large voltage drop,Then you have a bad connection or cable.
3.)Meter from Engine block to neg battery terminal,try to start truck,If you see a large voltage drop,Then you have a bad ground connection or neg battery cable/connection.
4.)stuck or bad starter can also pull battery voltage down while trying to crank it over
If you use a typical voltmeter/ammeter to do your trouble shooting , most of them can't handle large currents. 300 mA or 10 amp settings. If you have it inline with red battery cable and try to start the truck it will blow the fuse in the meter.