Replacing Reversing Light / Backup Switch - Guide

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[url=https://imoc.co.uk/app.php/kb/viewarticle?a=24&sid=d9b323455db671963ca5330e13356ff3]Knowledge Base - Replacing Reversing Light / Backup Switch - Guide[/url]

This is a guide to diagnosing problems with the reversing lights, and how to replace the switch. The procedure was done on a Rev3 Turbo, but I guess it's very similar for all revisions.

The reversing light circuit is nice and simple:

Car main power (i.e. with ignition to ON position) goes to fuse ECU-IG, then through the backup switch (mounted into the gearbox), then to the reversing lights.

If the bulbs check out OK and the ECU-IG fuse (located in the engine bay) is OK, and then it's probably the backup switch.

To check it is the switch and not the wiring (assuming you've checked the other things above):

- Turn off the ignition
- Disconnect the connector on top of the switch (has a press in tab to release it) <See pics below for location>
- Short (using a paperclip or stiff wire) the two sockets in the connector (simulating the switch in a closed position). If using a paperclip or bare wire, make sure it doesn't lie on anything metal! (I put a sheet of paper underneath)
- Turn the igntion to the ON position (you may need to click the alarm remote to allow the ignition to turn on)
- If the reversing lights light, it's the switch.
- Turn off ignition and remove wire/paperclip.

Toyota Part number is 84210-12040, "Switch Assy, Back-up", priced at £18.43 + VAT (less any discount). The switch comes with the required metal crush washer.
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Tools required:
- 27mm socket (usually 1/2" drive)
- Matching (1/2" drive) universal joint
- Long extension bar
- Ratchet or breaker bar
- Torque wrench for re-installation
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The back-up switch is quite tricky to get to, I removed the air intake boxes to get better access:
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Picture taken with camera looking from airbox location, connector removed:
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The switch needs a 27mm socket to remove it. Fit a universal joint to the socket, then manouver the socket onto the switch by dropping it (not literally) down to the right of the black hose shown:
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Fit a large extension bar onto the universal joint, ensure the socket is square on the switch and undo the switch with either a breaker bar or ratchet:
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Once the switch is loose, you can (just) get both hands down there and un-screw it by hand.

Fit the new switch and washer (using the same method as above), torque the switch to 40Nm, then re-attach the connector.
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Turn the ignition to ON, disable the immobiliser if necessary, and put the car in reverse.... there should now be light :D

Don't forget to re-fit anything else you'd undone!

Hope this helps,
Jon