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 Replacing Reversing Light / Backup Switch - Guide 
Description Guide to diagnosing and fixing reversing light faults
Author jrleech Date Tue Feb 07, 2006 10:00 pm Type Picture How-To

Category Engine
Viewer Comments [5 - Post your comments]
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Replacing Reversing Light / Backup Switch - Guide
Guide to diagnosing and fixing reversing light faults
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.

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

The back-up switch is quite tricky to get to, I removed the air intake boxes to get better access:

Picture taken with camera looking from airbox location, connector removed:

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:

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:

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.

Turn the ignition to ON, disable the immobiliser if necessary, and put the car in reverse.... there should now be light [Very Happy]

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

Hope this helps,

 User comments 
Hurstie1981: Sun Sep 02, 2007 11:34 pm    

I have been wanting to do this for ages and finally a KB entry has come up. Only problem is the pictures wont load?
BenF: Mon Sep 03, 2007 8:52 am    

Looks like Jon has removed the pictures from his webspace that were used for this article - perhaps PM him and ask if you can have copies of them?

There's nothing we can do from this end I'm afraid.
Drewvb1: Mon Jan 12, 2009 11:25 pm     Reverse switch location

This is interesting. I ordered this part and couldn't find the location on the engine/trans.

These pics are great but I am having a hard time getting oriented to figure out if there from the top or bottom:-( Sorry for the stupid question.

Also, mine is an automatic trans. I am assuming that this is for an automatic.
toxo: Fri Jan 16, 2009 1:39 am    

It's a bit different on the auto and the switch is a different part unfortunately [Sad] See here for info: http://www.imoc.co.uk/forums/viewtopic.php?t=110724
bobothemonkey: Mon Jun 29, 2009 9:02 pm     Fuse location?

This might sound silly, but where about in the engine bay is the fuse of the reverse lights? I have the same fault on my car, no reverse lights, can see how to change the switch but cant find the fuse you are reffering to.
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