These instructions apply to the Dodge Magnum Mk1 (LX) 2005-2008.
For other models, please choose your vehicle here.
Like the rest of the LX family, the Dodge Magnum (LX, 2005–2008) carries its battery in the back rather than the engine bay — in the wagon it sits beneath the cargo floor. There are remote under-hood terminals for jump-starting, but for a battery swap or electrical work you go in through the load area. Doing it in the right order protects the control modules.
Before You Start
- Park level, switch the ignition OFF and take the key out.
- Wait at least 3 minutes so the modules power down fully.
- Have a spanner or socket for the terminal clamps, gloves and eye protection ready.
Where the Battery Is
The battery is stored under a hinged access cover in the load floor in the cargo area. For a quick jump-start or charge you do not need to reach it — use the remote jump-start positive (+) post and the body/engine ground (−) in the engine compartment instead.
Disconnecting and Reconnecting
- Open the tailgate and lift out the load-floor panel to reach the battery.
- Slacken the negative (−) clamp first and lift it off the post.
- Slacken and remove the positive (+) clamp next.
- If swapping the battery, undo the hold-down and lift it out — it is heavy.
- Refit in reverse: battery in, hold-down on, positive (+) first, then negative (−) last. Nip both clamps tight and check for corrosion.
What to Sort Out Afterwards
- Clock and radio presets need re-entering.
- Auto-up/down windows need reinitialising — hold each switch fully up for a couple of seconds after raising the glass.
- Idle and shift quality may feel off for the first few miles while the powertrain computer relearns; drive normally and it settles.
Keeping the Battery Healthy
Because the battery lives in the enclosed cargo area, keep the terminals clean and lightly greased. Most last four to six years; test yearly after year three. A Magnum that keeps flattening its battery usually has a parasitic drain or a charging fault — and a flat battery back there is the most common reason the shifter jams in Park (see our emergency park-release guide).
Frequently Asked Questions
Why is the battery in the boot? The LX platform puts it there for weight balance and under-hood packaging; the under-hood posts are just remote jump points.
Why disconnect negative first? With the earth lead off, a spanner touching bodywork on the positive side cannot short out.
Will disconnecting clear my fault codes? It may drop some stored data, but it fixes nothing — a live fault returns after the next drive cycle.
Do I need a memory saver? Optional — plug one into the accessory socket to keep presets and learned values alive; otherwise just redo the steps above.
If a warning light stays on after reconnecting, our sister site autodtcs.com can help you decode it.
Independent guide — not affiliated with Dodge. Always follow your official service manual and safety precautions. Read our full disclaimer.