Technical boot open warning light

[Tropicalmike]

I have a constant door open warning light and boot open text comes up when turning ignition on . its a 2011 Lounge

I have dismantled the switch and boot release unit and tested the switch and it is good . The switch is a normally closed circuit when the boot is shut .
with switch disconnected ( open circuit ) makes no difference and i can detect about 7 v on the wire when disconnected and the earth connection from the switch is good . The boot release works correctly as does the boot interior light that are from the same unit

I suspect the boot open circuit in the passenger compartment fuse box is at fault but cant see how to get to the connector on the fuse box or remove the fuse box to try and check this . Possibly a high resistance on the wiring or connector at best

Any suggestions / experience appreciated

Thanks in advance

 

[chris3234]

Check the wiring running into the boot hatch
The wires often break inside the rubber tubing causing issues like this

 

[Tropicalmike]

Check the wiring running into the boot hatch
The wires often break inside the rubber tubing causing issues like this

Thanks Chris
I had a close look at the flexi rubber at the boot hatch hinge top initially but a broken wire would make the circuit open which how it should be when the boot is closed . I need to get to the connection at the passenger compt. fuse box and simulate the switch there.
Mike

 

[varesecrazy]

Thanks Chris
I had a close look at the flexi rubber at the boot hatch hinge top initially but a broken wire would make the circuit open which how it should be when the boot is closed . I need to get to the connection at the passenger compt. fuse box and simulate the switch there.
Mike

Do you mean no damaged wiring was found..

I was blaming the switch they day you 1st posted this.. but the other thread ended in damaged wiring..

Charlie

 

[Tropicalmike]

Do you mean no damaged wiring was found..

I was blaming the switch they day you 1st posted this.. but the other thread ended in damaged wiring..

Charlie

Hi Charlie
Wiring inside flexi boot rubber looked OK . That was one of my first thoughts about a broken wire after checking the switch at the latch/release with a multimeter. However, the boot switch operation shows the switch to be open circuit when the boot is closed. IE a broken wire elsewhere would mean the boot would appear as closed all the time ( no fault alarm ) . The wiring diagram in my Haynes manual confirms this. The boot interior light has a separate contact in the same latch unit and that closes when the boot opens . That is all OK as is the boot release solenoid circuit . I really want some practical advice on how to access the connectors and remove the fuse box under passenger side dash board so as to check the wire going to the boot switch doesn't have a partial earth fault or if it is electronics of the fuse box that is at fault.
Thanks Mike

 

[Tropicalmike]

Check the wiring running into the boot hatch
The wires often break inside the rubber tubing causing issues like this

correction on my original post . I am now doubting what I checked about the switch being normally closed with boot closed ( being opposite way around of the boot interior light switch ) I need to check again
Thanks guys

 

[Tropicalmike]

I have now managed to repair it . Once I identified the fuse box cover was secured by "shearhead" screws I managed to release them with some small mole grips ( Fiat really dont want anyone getting in there ! )
I could then get at the connector plugs .

I identified the connection on the multipin plug E for the boot open circuit and checked the wire resistance/continuity through to the boot switch. it was about 2 M ohm so virtually open circuit . OK to measure voltage at the switch but too low mA current to get the warning light off. So it then pointed suspicion back at the flexi section in the rubber sleeve at at boot hatch hinge.

I managed to access wiring loom inside car by nearside rear seat belt upper fixing . I then cut the small grey/white wire for the boot open circuit. Putting an earth on the open end back to fuse panel cleared the open light.

With the use of some wire from a coat hanger to "fish" a new wire through the rubber boot and boot hatch frame I connected in a new length wire through to the switch . Now all good and working correctly. Fortunately the other wires in that flexi hinge are all ok ( they are all larger cross section so have more wire strands )

No faulty warning light to fail the MOT next month which was the prime reason to get it fixed

Thanks for the input of ideas

 

[Little500ladybird]

Hello people. I now have a new 2017 jtd and wonder if anybody has a wiring diagram. I have the same fault, the boot open warning is always on. I don't know if the electronics are the same on the newer version? It's otherwise a great little car but this niggle has returned after going away for the last 12 months

 

[A3jeroen]

Hatchwiring? Microswitch in the lock?

gr J

 

[John202020]

Hatch wiring 6+ years old prime time for failure especially if the boot has been opened often?

 

[Little500ladybird]

Yes, boot has indeed been well used (doggy transport)
I shall see about running a new wire/s through that rubber boot. Presume this is the common problem area?
I'll try and use ptfe insulated wire instead as this can take the flexing a little better
What colour is the offending wire/s please?

 

[John202020]

Yes, boot has indeed been well used (doggy transport)
I shall see about running a new wire/s through that rubber boot. Presume this is the common problem area?
I'll try and use ptfe insulated wire instead as this can take the flexing a little better
What colour is the offending wire/s please?

You need to completely rewire the flexible using say silicone covered test meter cable(very fine strands) for a proper long term fix?