Disconnect and Reconnect the Battery

Before any electrical work on a 2015–2020 Ford F-150 (P552) you disconnect the 12 V battery. Doing it in the correct order stops a wrench shorting the live post to the body and protects the truck’s electronics; reconnecting in the right order avoids a surge. This is the US-market procedure.

1. Park, ignition off, key out, and leave the doors closed for a couple of minutes so the modules go to sleep. Put on eye protection.
2. Open the hood. The 12 V battery sits in the engine bay (passenger side on most P552 F-150s).
3. Loosen and remove the negative (−, black) terminal clamp first. Tuck it well clear so it can’t spring back onto the post.
4. Then loosen and remove the positive (+, red) clamp.
5. Do your work. With the battery off, the clock, radio presets, oil-life monitor, TPMS and one-touch windows may need re-setting afterward.
6. Reconnect the positive (+) first and tighten it, then the negative (−). Make both clamps fully tight.
7. Switch on, check for warning lights, reset the clock and presets, and re-initialise the one-touch windows if they’ve stopped auto-closing.

FAQ

Which terminal comes off first?

Always negative off first and positive on first. It keeps a slipped wrench from bridging the live positive post to the grounded body.

Will I lose my settings?

Expect to re-set the clock, radio presets and oil-life monitor, and sometimes to re-initialise the TPMS and one-touch windows.

Do I need a memory saver?

Optional. A memory saver plugged into the OBD port keeps presets alive, but it leaves the system live — so keep tools well clear of the terminals while you work.

My windows won’t auto-close after reconnecting.

Re-initialise each one: hold the switch fully up until the glass stops, hold 2 seconds; then hold fully down, hold 2 seconds.

If the truck stores fault codes after reconnecting the battery, look them up on autodtcs.com.