: Hi all ,have just joined so here goes . Im hoping theres some one who can help me. I own a 54 reg 1.9 JTD Dynamic Stilo multi wagon. the other day I noticed that the reversing lights were not working . So after reading posts on here I replaced the gearbox switch , and they still dont work . have checked fuse 31 ,is ok and theres power at the fuse . how ever , when you take wires off the switch theres no power there , with ignition on I might add. the bulbs are ok ., theres no audible beep , parking sensors arent working either , and with front wipers on and car in reverse the rear wiper also does not come ,it used to do . I am at a loss .Can anyone help timo

Hi Tim, Welcome to the FF.

The reversing light switch wiring goes throught the infamous D4 connector. This connector can cause various problems on Stilos and probably needs cleaning.

There's a guide to cleaning it here: https://www.fiatforum.com/stilo-guides/99828-d4-connector.html

Yes that's a darned good place to start


Check for power on pin A8 on connector D4- look for the wire colour A = light blue


If there's no power arriving at D4 then the problem might be a lost contact at the body computer connector A

thanks guys weather permitting I will take a look this weekend , see if I can find this D4 connector.

Well have looked at connector D4 and can say that it looks alright no water or dampness to speak of , only getting a reading of -2.3 on the blue wire that goes to the gearbox switch {there being 2 wires the blue and a pink} On pin A8 there dosent seem to be any power at all [Ignition on} can only assume it is this body computer connecter 8 , but where is that located.? Some one on an earlier thread suggested a connector under the rear bumper, offside I think it was , could it be that. Would that stop power being at the switch , any more thoughts anyone Cheers Tim.

No, your problem is in the circuit from the battery to the rev switch won't be anything to do with parts of the circuit downstream from the rev switch

Firstly, double check you have power at fuse F31 7.5A - people have been known to check the wrong fuse. Sorry for stating the obvious but it can save a lot of head scratching

You say "only getting a reading of -2.3 on the blue wire that goes to the gearbox switch" so that's where the problem is. When you see 12v there then things willl be normal. I assume you're reading voltage from the blue wire on the rev sw to battery neg, yes?


Ok next stop is fuse panel under the bonnet B1.


There's a 32 pin connector (connector A) there underneath the panel. The blue wire on its pin 11 is power in from the body computer and it then simply links across to pin 10 of the same connector to supply power out to the rev switch. So check you have 12v on the blue wire to pin 11 there. If you have then when connected to the fuse panel it should give 12v to the blue wire on pin 10 then thru connector D4 to the rev switch

There's no real need for the rev sw power supply to go through the B1 connector so if you have any problems there then you could simply connect the light blue wires together and eliminate the connector link

yes blue wire, on wires that go to reverse switch to negative on battery . as you say with ignition on there should be 12v between blue wire and neg terminal on the battery, but im reading -2.3. It will be the weekend now before I get a chance to look at it again , thanks for further info will post results if I get any where thanks Tim.

... -2.3v!?

how did you get a negative voltage? were you using your multimeter the wrong way round?

2.3v on a 12v system imho sounds like a broken wire or corroded/burnt out connection. burnt out connections will give high resistance dropping the desired voltage, my cinq went through 4 O/S H/Light connectors for this very reason whenever i topped up the screen wash it was inevitable some would dribble on the connector it was a slippery slope from there:yuck:

Give the blue wire and the loom that it sits in a wiggle, pay attention to tight-ish bends and places its secured, make sure its not rubbing against anything if it is be sure to check for broken wires.

Whilst leaving your multimeter hooked up see if the voltage shoots up to 12v or drops off to 0v, wherever you wiggle it and the value changes is where your problem may be

fiat stilo 1.9 multi wagon 54 reg. Re- no reversing lights. If you find that fuse f31 in fuse box next to steering column is ok and you have power to same , but when you check for power at the gearbox switch there is none{blue wire} then here is the solution. having first determined that the gear box switch is ok , this is what you do. Take a piece of wire say 10 inches long or so , fit an in-line fuse holder with a 7.5 amp fuse {this is what f31 fuse is for original feed} With ignition off look up fuse location of f24 in fuse box next to the battery. [PP312 In hand book shows location,theres a diagram to show where it is } f24 is power steering fuse supply live only with ignition on. remove fuse and bare a small amount of the wire at one end .Insert this where f24 where fuse sits ,then re-fit fuse to hold wire in place. Bare the other end , a bit longer this time and having first got into the insulation to reveal the two wires that go to the gearbox switch {ie one is blue the other pink} splice your new feed wire to the blue . and hey presto we are working again . I did it yesterday and I ASSURE YOU IT WORKS .reverse lights, parking sensors and wash wipe [IN REVERSE GEAR FRONT WIPERS ON} ALL WORKING . rEGUARDS TO YOU ALL TIM