My reverse light hasn't been working. I only found this out recently whilst meeting a gritting lorry on a narrow lane at night. With the windows steamed up and putting it into reverse, there was nothing behind but darkness. I stuck my head out the window and half drove up the hedge trying to find the gateway i'd only just passed.
The reverse light is part of the MOT, so it'd have to be done sooner or later. Fundamentally, there's either a problem with the bulb, the wiring, the switch or the supply. First off, checking the bulb - it hasn't blown. Checked the connections for voltage - nothing. So it was either the switch or the supply.
You can work this out very easily by removing the middle seat/cubby box floor. The black connector from the loom to the reverse light should be staring at you in the face. It loops around the left hand side of the gearbox to the switch (seen in the mirror).
Pull apart the plug and check the voltage on the green and green/brown wires. If you have something, then the supply is getting there. Mine was, therefore the switch is the problem. The switch wasn't done up tightly and could be unscrewed by hand. To make sure, on the bench I measured the resistance on the switch terminals with the plunger pressed in. There was no reading so it was definitely dead. Sometimes the switch can get has worn down and isn't depressed enough by the gearbox action. This can be remedied temporarily by removing the washer and replacing the switch.
What you'll need
- Reverse light switch - AMR3918 - about £10
- 19mm spanner
It's just a case of screwing the new switch into the gearbox. The workshop manual recommends removing the gearbox tunnel, which would make it a lot easier but I didn't want the hassle. You need to make sure that the wires rotate as the switch screws in, otherwise they will twist and remove the insulation (as can be seen on the old switch).
I was able to feed the 19mm spanner over the connector and down to the casing to nip it up. You're supposed to tighten to 24NM, but with no way of getting a socket on with the wires, i'm not sure how this is possible. Either way, I did it up as tight as I could in the surroundings.
And there is now one working reverse light.