These instructions apply to the JAC S2 (2021-2023).
For other models, please choose your vehicle here.
Disconnecting the 12 V battery on your JAC S2 (2021–2023) is a straightforward job you might do before fitting a new battery, ahead of winter storage, or when you need to work near the airbags and seat-belt pretensioners. It is also the first step in recovering a car that has been sitting with a flat battery. Done in the right order — negative off first, positive on first — the S2 powers back up and relearns its settings cleanly, so this is well within reach of a confident home mechanic with a single spanner.
Where the 12 V Battery Is
On the JAC S2 the 12 V battery sits in the engine compartment, in the usual front corner. It is generally held down by a clamp and may have a plastic terminal cover that lifts or unclips away. Once you can see it, identify the two terminals: the negative (−), marked with a minus symbol and normally a black lead, and the positive (+), marked with a plus and often protected by a red or coloured cap. Confirm which is which before you loosen anything — the order you work in is what keeps the job safe.
First, a Few Checks
- Make sure the ignition is fully off and the doors are closed so the electrics settle.
- Remove the key and keep it away from the car so it cannot wake the systems.
- Switch off the lights, climate, and any accessories, and unplug anything from the 12 V or USB sockets.
- Note down your radio presets and any security code, plus the clock setting, so you can restore them afterwards.
- Wait a couple of minutes after switching off so the control modules power down.
- Wear gloves and eye protection, and have the correct spanner ready for the terminal clamp nut.
Disconnecting Safely
- Switch everything off and remove the key, then wait a couple of minutes for the modules to sleep.
- Lift away any terminal cover so you can reach both posts.
- Slacken and lift off the negative (−) terminal first, then tuck the lead aside so it cannot spring back onto the post.
- Next slacken and remove the positive (+) terminal, and cover the exposed post so it cannot short against bodywork.
- Working near airbags or seat-belt pretensioners? Wait a few minutes more after disconnecting before you begin.
Reconnecting
- Refit the positive (+) terminal first and tighten its clamp until it is secure.
- Refit the negative (−) terminal last and tighten it the same way.
- Check both clamps are firm — a loose terminal causes flickering warnings and hard starts.
- Allow the car a minute to settle before starting and driving.
What You’ll Need to Reset Afterwards
Cutting the 12 V supply clears the short-term memory in several systems. On the S2 you may need to sort out:
- Clock and radio presets — reset the time and re-enter your stations and any audio security code.
- One-touch windows — if a window loses its auto function, hold the switch fully up at the top limit to relearn it, then repeat at the bottom.
- Driver and comfort settings — some personalisation may return to default and need setting again.
- Warning lights — a few dashboard alerts appear on first start-up and self-clear once the car has been driven a short distance.
A straightforward like-for-like 12 V battery of the correct size and rating does not normally need any coding on this car.
If a Warning Light Stays On or the Car Feels Off
- Re-check that both terminal clamps are tight and clean — a poor connection mimics an electrical fault.
- Take the car for a short, gentle drive to let the systems relearn and clear first-start messages.
- Re-do the window relearn if one-touch is still not working.
- Rule out a genuinely flat or worn-out battery — if it will not hold charge, disconnection was not the real cause.
- If a light persists, it has stored a fault code — look it up on autodtcs.com.
Frequently Asked Questions
Where is the battery on a JAC S2?
In the engine compartment, in the usual front corner. It is normally clamped down and may have a plastic terminal cover that lifts away to expose the negative and positive posts.
Which terminal do I disconnect first?
Always take off the negative (−) terminal first and refit it last. Reconnect the positive (+) first when you put things back. That order avoids any risk of a short across the terminals while you work.
Will I lose my radio code?
If the audio system uses a security code, note it down first along with your presets and clock. After reconnecting you simply re-enter the code and reset the time, and your stations are back.
How long should I wait before working near the airbags?
Give it a few minutes after disconnecting before you work on the airbags or seat-belt pretensioners, so any stored charge in the restraint system has bled away safely.
Does a new battery need coding on the S2?
A like-for-like replacement of the correct size and rating does not normally need coding for an owner. Fit the same specification the car came with, make sure the clamps are tight, and let it settle before driving.
Will disconnecting the battery clear fault codes or a warning light?
It can clear temporary codes and their messages, but a genuine, ongoing fault will log again as soon as the car powers up. If a light returns straight away, read the stored code rather than assuming the battery fixed it.
If a warning light stays on after reconnecting, look up the code on autodtcs.com.
Independent guide — not affiliated with JAC. Always follow your official service manual and safety precautions. Read our full disclaimer.