Battery light on after computer replacement

[Sambosat]

Hello;

I have Explorer 2010. My car computer broke and I replaced it with a used one where I had the other reprogrammed and everything works fine except one small thing. The car battery comes in even though there is no problem with the alternator. When I click on the reset button inside the car the battery light turns off but after 10 min it would light up. Any hint would be appreciated and thanks again for your assistance

 

[Sambosat]

Ok here is some update and I hope that someone might have an idea on what it the cause and how can it be fixed. I took the car to the mechanic yesterday and he read the charge coming from the alternator and he told me that is was giving between 12.5-13V and the correct reading should be at 14 so he said that this might be the cause of the light coming on. I had the alternator replaced with a new alternator from the dealership and got it installed and the charge reading is at 14 now but the problem is that the battery light still comes on and we are not sure why. Anyone can advise?

 

[Sambosat]

Hello again; It seems that no one is able to give any possible reason for this problem not sure why. Maybe because there is not much information?!?!?
I have also tried the following. I have kept the engine running and disconnected the battery and the car did not stop which means (correct me if I'm wrong) the alternator is not the cause of the problem. I have searched the internet but seems not able to find a solution not sure why. Is this problem never happened to anyone. I mean is this new. The battery light is somehow annoying but I can live with it as long as this would not affect the car nor the battery. Thank you guys for your help

 

[1991 sploder]

Hello again; It seems that no one is able to give any possible reason for this problem not sure why. Maybe because there is not much information?!?!?
I have also tried the following. I have kept the engine running and disconnected the battery and the car did not stop which means (correct me if I'm wrong) the alternator is not the cause of the problem. I have searched the internet but seems not able to find a solution not sure why. Is this problem never happened to anyone. I mean is this new. The battery light is somehow annoying but I can live with it as long as this would not affect the car nor the battery. Thank you guys for your help

Hold up

 

[1991 sploder]

The alternator should go through duty cycles low-med-high....as part of what ford calls a smart charge. The light on the dash is directly from the computer. What ur looking at is a low voltage anytime during those cycles. Noticed u replaced alternator but did u replace the battery? I will correct you because the charging system requires a battery that holds with engine off at least 12.?2+ Overnight if it doesn't that light will always be on. Also it is on when u turn key but don't start? Battery needs to be load tested and charged... If u drop below 13.8 while running or 11.5 off the light will be solid... U need data stream ecm/pcm voltage from a scanner yea 14v @ some point but the light is telling u something is wrong with the battery not necessarily the control module because when it's running it will throw a p0562 low voltage. Put a multimeter on the negative terminal to the body should be less than 4-5 ohms if not fix it...most probable cause...what is the date sticker on the battery say?

 

[Sambosat]

Thank you SP loader and finally I got something going. Both battery and alternator are new and when I start the car The light does not come on right away. It takes about a minute then it appears and then it stays there even when the engine is running. I press the reset button it disappears but it comes back on after 10-15 min. I have checked it with different scanners but did not get the P0562. Actually now there is no code that is showing

 

[1991 sploder]

Check the ohms from ground to frame should be less than 5 ohms...with data stream from scanner not dropping below 13.8v running...nice I tell everyone replace battery and alternator together. So did u get a alternator with the same code on it as the old one? Needs to be ford/motocraft.

 

[1991 sploder]

U should measure the battery directly also 12.5-13.5 for smart charge not 14v running 12.probably 6 off also multimeter is required u should test ground between block and frame less than 5 ohms. Since it is smart charge u need to make sure it's a smart charge alternator.

 

[1991 sploder]

Measure from the connection on alternator 2 outside pins to ground. Either one is battery voltage other is duty cycles need 5-10v

 

[D Hook]

You might want to do some research on the technique of disconnecting the battery while the engine is running. There's a good chance of causing alternator problems like burning out diodes and then frying other electronics when voltages spike. (See article below).

Don't Disconnect the Battery with the Engine Running

Never disconnect the battery when the engine is running

www.troubleshooters.com

I had a dodgy alternator for awhile also. Battery light would turn on, I'd reset it and then it would be fine for months. Then it started to show the red light more often and when i took it to the dealer they diagnosed a bad alternator. Got it changed and no light since.

You might want to pick up a meter and when the light comes on, before resetting it, check the voltage at the battery while it's still running. Mine would start out fine and then after a few minutes, the voltage would slowly drop across the terminals as I drove until it finally lit the light up. When I would check, the voltage was around 12v, sometimes lower. New alternator fixed it all. I know you've replaced yours but it's possible you got a bad one. Also, check wires in harness from alt. to battery. How many wires are coming out of the back of the alternator plug...2 or 3?

 

[D Hook]

Do a search on "alternator" and quite a few threads pop up. Here's the one I posted a few weeks back:

What brand alternator is recommended? Reman or rebuilt?

2006 V-8 Explorer. Looking to change out the alternator. Keep getting a red battery light indicator come on in the dash window where compass usually displays. It's very intermittent but consistently comes on after driving in town for a few minutes. When I hit RESET, it goes back to normal...

www.explorerforum.com

 

[Sambosat]

Check the ohms from ground to frame should be less than 5 ohms...with data stream from scanner not dropping below 13.8v running...nice I tell everyone replace battery and alternator together. So did u get a alternator with the same code on it as the old one? Needs to be ford/motocraft.

For the resistance I got 2.8 ohm between ground and frame and yes I got a motorcraft alternator

 

[Sambosat]

You might want to do some research on the technique of disconnecting the battery while the engine is running. There's a good chance of causing alternator problems like burning out diodes and then frying other electronics when voltages spike. (See article below).

Don't Disconnect the Battery with the Engine Running

Never disconnect the battery when the engine is running

www.troubleshooters.com

I had a dodgy alternator for awhile also. Battery light would turn on, I'd reset it and then it would be fine for months. Then it started to show the red light more often and when i took it to the dealer they diagnosed a bad alternator. Got it changed and no light since.

You might want to pick up a meter and when the light comes on, before resetting it, check the voltage at the battery while it's still running. Mine would start out fine and then after a few minutes, the voltage would slowly drop across the terminals as I drove until it finally lit the light up. When I would check, the voltage was around 12v, sometimes lower. New alternator fixed it all. I know you've replaced yours but it's possible you got a bad one. Also, check wires in harness from alt. to battery. How many wires are coming out of the back of the alternator plug...2 or 3?

Oh I did not know about the alternator might get fried uf you disconnect battery while car is still running. I hope I did not kill my newly installed alternator. The light comes every 15 min. I will try to measure the voltage. If it reads below 12 what would that mean?

 

[D Hook]

Assuming the belt isn't slipping and the wiring is not corroded, I'd look at the alternator next.

Which computer did you replace? The one under the hood on the passenger side?

 

[Sambosat]

I replaced the main under the hood ECM

 

[D Hook]

Curious if the problem is fixed. And what fixed it.

 

[Sambosat]

No the problem is not fixed. My iriginal ECM was sent for repair and now got it back. I wanted to check if I install back my original ECM will all my problems disappear ir not. But now Im faced with the antitheft system that not accepting my keys so I need to reprogram my keys

 

[BrownsFan42]

2007 4.0 Eddie Bauer. My red “Check Charging System” light goes on periodically. It goes off when I accelerate. When it’s on, multimeter shows 14.47 volts. Can’t be the alternator. And since it’s charging, I’m not going to worry about it.

 

[Dyeril 21]

Having the same problem after computer change. its running at 13.3-13.5v while running. Was yours fixed?