02 Mondeo reversing lights

I know you say there is no power, but Have you tried just connecting the two switch wires together (ign on)? switch failure is very common on this model and I have replaced several (on top of the box below the battery on the six speed diesel I did a couple of weeks ago), there is iirc a separate fuse (or was it a possible three) for the reverse lights. and you should not handle the glass of the bulbs as the bulbs are halogen type.

Mine have stopped working. Bulbs OK, fuse OK, switch OK. There seems to be no power to the switch. This seems to indicate a faulty ignition relay (looking at the wiring diagram) but if it were, this would cause problems elsewhere, wouldn't it. Plus, I don't know where this relay is. Any pointers anyone?

Ta

Rob Graham

Yes.

Haynes shows just the one fuse. However, it also shows a relay and because I can't find any power in the circuit anywhere from and including the fuse terminals back to the bulbs I'm thinking the relay is malfunctioning. Question is, which one is it and does it reside in the box of relays next to the battery? You mention "on top of the box below the battery". Does "box" mean gearbox. My switch is on the gearbox, but there is a box NEXT to the battery with relays in it.

and you should not handle the glass of the bulbs as the

I can't see a relay from your description. The inside of lid the auxiliary fuse box next to the battery has a map of the fuses/relays but none of them is labelled 'reverse' and the layout does not correspond to your description (mine's diesel, BTW).

The presence or otherwise of a reverse relay may depend on the exact model. Autodata doesn't make that clear, showing some "dotted" options.

For example, the relay might be to auto-switch the rear wiper, which won't be needed if it doesn't have that option, or it might only be used with auto transmission.

Chris

I would have a check that powering one or other of the wiring connectors at the switch will actually make the reverse lights work, if it will, then supplying a power feed to the other is relatively trivial and will fix the problem.

Something occurred to me: do not take offence, but when you say that you have tried shorting the reverse switch connectors and the reverse lights do not come on.: have you actually located the reverse switch? (as opposed to the speedo sender.)

Sounds like a good idea. However, is it not true that the ECU gets a signal from the reverse light circuit (not sure exactly from which bit) and puts the engine into some different mode or other (a bit vague because I don't know what this might be and whether it's even a fact). If it's so, then excluding the relay from the circuit might be detrimental , yes/no?

AKAIK it's the reverse light switch, judging by the picture in Haynes. Might I have made a mistake?

Mmmmm. The mystery deepens. Haynes' wiring diagram appears to show a relay serving the reverse switch, but no actual picture of the fuse box with the lid off, and the lid doesn't show this relay on its map inside it.

On Wed, 27 Oct 2010 15:27:01 +0100, Rob Graham boggled us with:

They're not known as the Book of Lies for nothing... ;-)

Indeed, but either you believe them or you don't buy the book. Having got the book, I believe I have found the reversing switch, but you tell me, am I wrong?

Easiest way to check is to identify and compare the wire colours. At least with a Ford, that is likely to correspond with the manual.

With cars like the Mondeo, there are so many variants and trim levels, if a complete wiring diagram was made available for every possibility, there would be no room in the manual for anything else!

Chris

Yes, these do

Thanks for all your help on this one, guys. It turns out to be the switch after all - as Mr C strongly suggested. It's odd that my multimeter test showed the switch to be working, plus I was thrown by the fact that the circuit is the earth side of the bulb, so no wonder I wasn't getting any power there!

Rob

if the switch earths the light to make it work, then a multimeter should still show voltage, so that is odd.

Yes, it is odd. I think the best that can be said for my efforts in this case is 'pathetic'!.

We've all been there; good you "'fessed up", and better still you fixed it!

Chris

I wasted several hours quite recently on a very minor electrical job: in a ford door the electric window winder had stopped, when I investigated I found that the double bullet connector had rusted away although all the wires were fine, so I went to my box of tricks and found a double bullet connector , plugged in the bullets and tried it: nothing, but the lights all dimmed, so I assumed that the electric motor assembly was jammed, took the motor out, tested it and found it worked ok, put it back, exactly the same, no movement and the lights dim. Much head scratching later I realised that the double bullet connector that I had used was actually a multi way, as opposed to two separate ways in one lump. So when the wires were all in the connector it was just putting power straight through to earth and not getting to the motor at all. So yes, everyone does things that look stupid in retrospect.

In message , Mrcheerful writes

I haven't seen a bullet connector for yonks, I think I threw away the tin of spare connectors away after keeping them in the garage for a while. I take it we're talking about an old-ish car, or are they still in use?

Damn sight easier to plug in and out than the multi plugs on wiring looms.

yep, it was my own Xr4x4, so 1986, it was the type of bullet connector like motorcycles used to have, I assume it was original, I had never really looked before. The ends of the wires had soldered on brass connectors, which does not sound like ford, so maybe someone had been in there before me (pre 1997)

How do you make yourself throw stuff away, I am drowning in piles of stuff that I have kept for too long, just in case.