Turn key to On when replacing battery & using a memory saver?

[extrap]

When using a memory saver / maintainer when replacing the GT's battery, do I need to turn the key to On?

I feel like the answer is Yes if using a memory saver thru the 12V power outlet on the dash, and No if using a memory saver thru the OBD-II port, but please let me know.

Thank you ...

 

[PeteK]

IIRC, the cig lighter/outlet on the dash is always hot. Therefore you do not need to turn the key to the ACC or ON position. Just plug it into the outlet. I'm not sure about the OBD2 port.

 

[twobjshelbys]

If you plug in through the dash port don't turn the key on. The draw could exceed the capacity of the tender. I don't know what the "idle current" is nor the amp capacity of the Ford tender but you don't need to turn it on.

Be sure to black tape off the positive battery terminal as you don't want to accidentally short it to ground with the tender live.

 

[Tomcat]

I did NOT use any electrical "support" during the battery change (as I feared shorting, etc...and my area in Florida does not have emission testing). That being said, I had no issues (other than resetting radio presets) and no caution/warning lights.

 

[dreimer]

When I changed my battery 2 or 3 yrs back, I didn't use any electrical support (same reason as Tomcat). As you know, Extrap, I am in Florida too. No issues and no caution/warning lights either. My car has a pulley/tune/long tube headers mod.

Hardest part was taking one of the clamps off one of the terminals. Forget which one. I think the Incredible Hulk must have tightened the last battery. I am a serial over-tightener, but this was off the charts!

 

[twobjshelbys]

Replacing the battery (actually just disconnecting the battery) is one way to clear a "Check Engine Light"; it does not create a CEL event. (There is actually a pending code which is that the adaptive tests need to run.)

So if you replace the battery without putting a backup on you clear all the adaptives and have to run the drive cycle. If you're replacing the battery coming up on an OBDII based emissions test you're well advised to plug the charger in. Otherwise nothing bad happens.

The drive cycle if you have the right conditions can be done fairly quickly. The first time I ran it it took 300 miles and a month of short trips to the car show down the street. If you drive the specific start/stop/idle/run steps you can knock it off under 40 or 50.

 

[extrap]

Replacing the battery (actually just disconnecting the battery) is one way to clear a "Check Engine Light"; it does not create a CEL event. (There is actually a pending code which is that the adaptive tests need to run.)

...

Well, funny you should say, cuz right now I have a CEL, but the OBD2 reader I have shows no codes stored or pending. That's with a Key On Engine Off test. It's been on my to-do list for a while to do an engine on test. Do you think I should try disconnecting then reconnecting the battery first?

Thanks for the replies, all ...

 

[twobjshelbys]

My truck puts on the check engine if I key on but don't start within a certain time. I guess it's a reminder to check the engine!

 

[PeteK]

If you plug in through the dash port don't turn the key on. The draw could exceed the capacity of the tender. I don't know what the "idle current" is nor the amp capacity of the Ford tender but you don't need to turn it on.

Be sure to black tape off the positive battery terminal as you don't want to accidentally short it to ground with the tender live.

I have not measured the electrical load of turning the key to Accessory, or ON, but based on my measurements on other cars, I will guess the the electrical load for Accessory position is significantly less than 5 amps, even with the radio on. IN the ON position, it is higher becuase the ignition is energized, but probably around 5+ amps. With the lights off, I have been able to charge car batteries with a 6 amp charger and the key ON. If your charger only delivers 5 amps, it may not keep up with the electrical load of the key in the ON position. It should be okay in the Accessory position. That's an educated estimate, so don't whine to me if it doesn't work for you.

Extrap: Reinforce what Tomcat said. If you don't have to go to an emissions test soon, just disconnect the battery. You probably won't even notice any difference in how it runs after you restart it. I don't.

I think some of you are overthinking this. Disconnecting the battery to change it or reset the OBD codes won't hurt anything. I've used a plug-in to the cig lighter to preserve memory configurations in more complicated radios, but the radios in the FGT are pretty simple and easy to reprogram the stations.

 

[GT@50]

I have not measured the electrical load of turning the key to Accessory, or ON, but based on my measurements on other cars, I will guess the the electrical load for Accessory position is significantly less than 5 amps, even with the radio on. IN the ON position, it is higher becuase the ignition is energized, but probably around 5+ amps. With the lights off, I have been able to charge car batteries with a 6 amp charger and the key ON. If your charger only delivers 5 amps, it may not keep up with the electrical load of the key in the ON position. It should be okay in the Accessory position. That's an educated estimate, so don't whine to me if it doesn't work for you.

Extrap: Reinforce what Tomcat said. If you don't have to go to an emissions test soon, just disconnect the battery. You probably won't even notice any difference in how it runs after you restart it. I don't.

I think some of you are overthinking this. Disconnecting the battery to change it or rest the OBD codes won't hurt anything. I've used a plug-in to the cig lighter to preserve memory configurations in more complicated radios, but the radios in the FGT are pretty simple and easy to reprogram the stations.

I finally found the clock, how do I set it? lol

 

[fjpikul]

Look in your owners manual

 

[nota4re]

My truck puts on the check engine if I key on but don't start within a certain time. I guess it's a reminder to check the engine!

Part of the OB2 requirements is that the vehicle must illuminate that CEL with key-on so that the owner and/or inspector can confirm that the light has not been tampered with.