Technical Electrics went crazy and now no power

[Ebsworth99]

Hi Guys, Im looking for some advice. About a week ago my wife rang me saying the car was displaying a message "Check keyless entry system" it later began to show up faults on several systems including airbag abs etc which would come up and then immediately disappear. I told her to bring the car home and park it up.
When I got home from work I went out to the car and tried starting it. There was a constant flicking message on the display saying check keyless entry system. The Ignitiom would not come on and the car would not start. None of the accessories would power up and the only things showing any life was the hand brake led and a couple of dash lights. The central locking was still working normally at this point.
I assumed it was probably a bad 12v battery and ordered a replacement.
I went out to the car the following morning and everything was completely dead! No central locking no sign of life at all.
I crawled under the car and was able to manually undo the bonnet release and again access to the engine bay. I did a quick check on the existing battery and got a reading of about 12.2v. I was expecting it to be lower but i guessed it could still be bad as its several years old.
once the new battery arrived I removed the old battery and replaced it with the new one. The voltage came up to 12.6v but still the car was dead.
My next thought was ok perhaps its not fully charged, So i got my jump pack and connected that too. The voltage now read 13.5v but nothing changed no relay clicks no noises at all nothing.
Ive been all over the engine bay and checked any grounding points i could find and also the main ground from the battery. It all checked out and had good connections.
Ive checked each fuse and they are all intact and appear good. Ive checked the under bonnet relays and the seem to be operating correctly with 12v applied.
So I started going through the fuses looking for power at each one. This is where I found something strange. Most the fuses have a 12v supply with the battery connected except 4 of them. I have attached an image of the 4 that don't show any voltage. The odd thing is that if i remove the main negative terminal those fuses then show 12v? Maybe this is normal behaviour? I cant find any information online to say whether it is or not.
So that's where I'm at and I'm completely stumped on how to proceed? I cant get into the car to test anything else because I have no central locking and when I try the manual key lock in the drivers door the key turns and doesn't unlock the car.
I really appreciate any feedback or advice you can give me.
Thanks

 

[varesecrazy]

Hi

@s130 will be familiar with the kit on a 500x

You have covered the obvious certainly

The forums excellent Search found this :

Check Keyless Entry System Warning | FIAT 500X

I have a 2015 Fiat 500X multi cross jet and I’m having issues with the car. The warning light and message keeps popping up saying “check keyless entry system” and the car runs fine. But one day I went to leave my house and the car wouldn’t start. Just kept flashing erratically “check keyless...

www.fiatforum.com

 

[s130]

First of all the manual key should unlock the door. It does on my 500X (2015) and as I recall even if the deadlocks are set. Are you sure you are fully turning (either direction). There will be no click/clunk as the central locking is not activated.

Not sure which 4 fuses you are referring to so below is for all of them. The legend on the left is faint so also refer to your fuse box (PDC) cover to be sure.

ALSO NOTE! The body computer contains a bunch of fuses which you will see include the central locking, keyless etc.

 

[varesecrazy]

Hi Guys, Im looking for some advice. About a week ago my wife rang me saying the car was displaying a message "Check keyless entry system" it later began to show up faults on several systems including airbag abs etc which would come up and then immediately disappear. I told her to bring the car home and park it up.
When I got home from work I went out to the car and tried starting it. There was a constant flicking message on the display saying check keyless entry system. The Ignitiom would not come on and the car would not start. None of the accessories would power up and the only things showing any life was the hand brake led and a couple of dash lights. The central locking was still working normally at this point.
I assumed it was probably a bad 12v battery and ordered a replacement.
I went out to the car the following morning and everything was completely dead! No central locking no sign of life at all.
I crawled under the car and was able to manually undo the bonnet release and again access to the engine bay. I did a quick check on the existing battery and got a reading of about 12.2v. I was expecting it to be lower but i guessed it could still be bad as its several years old.
once the new battery arrived I removed the old battery and replaced it with the new one. The voltage came up to 12.6v but still the car was dead.
My next thought was ok perhaps its not fully charged, So i got my jump pack and connected that too. The voltage now read 13.5v but nothing changed no relay clicks no noises at all nothing.
Ive been all over the engine bay and checked any grounding points i could find and also the main ground from the battery. It all checked out and had good connections.
Ive checked each fuse and they are all intact and appear good. Ive checked the under bonnet relays and the seem to be operating correctly with 12v applied.
So I started going through the fuses looking for power at each one. This is where I found something strange. Most the fuses have a 12v supply with the battery connected except 4 of them.
I really appreciate any feedback or advice you can give me.
Thanks

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The excellent info from @s130

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