Technical Fiat 500c Dead Roof

[Jiggie]

Hi All, after exhausting pretty much everything I can think of, including just getting in the car every couple of days and pressing the roof open button with my fingers crossed, I was hoping that someone can give me an idea on how to fix what seems to be an unusual 500c roof problem....

I bought a 1 owner 22K miles 2010 550c off a family member as a first car for my son and have been trying to get it ready for him. It definitely needed a lot of TLC which I've sorted (mostly), but I seem to have caused a problem for myself.

A day or so after getting the car I noticed quite a heavy leak from the thermostat so I replaced it with a new one (having to disconnect the battery to do so). All good and everything is fine apart from the roof seems to have no power. It was definitely working when I picked the car up.

I've checked through common roof problems and

1. The boot opens fine
2. The rear demister lights up when pressed (and I assume works)
3. The roof fuse has been swapped with a known good one
4. All rear lights work as expected
5. I can't see any problems with the boot wiring loom (but haven't stripped the cover back)

The answer to roof problems seems to usually be run the roof reset procedure, but in this case the roof doesn't move at all!

The only other suggestion I've been able to find is that the relay sometimes blows but I haven't been able to track down which relay the roof would use.

My last resort is to try to get access to the actual motor to have a look but there are 1001 inaccessible clips holding the trim on and the boot was definitely not designed to have someone climb inside....

Any help or advice would be very appreciated!

 

[Piccolo Nero e Bella]

Hi;

Have you tried to open and close the roof manually using the nut in the boot? If it's free to move then the problem must be electrical. How about disconnecting the battery for half an hour to reset everything and then trying again?

Can't think of anything else offhand. The control module is also behind the trim in the boot I understand!

 

[Jiggie]

Hi

I did disconnect the battery again for a while but it didn't make any difference.... I'll try it again just to make sure though!

I'm 99.9% sure it's an electrical problem but I'll give the manual opener a go just to make sure that it works - I feel like I've tried pretty much everything else!

Yes, I think the control module and motor is behind the boot trim, but have you seen the amount of clips holding it in and where they're located? I'm just not that flexible

 

[Piccolo Nero e Bella]

I had a few clips out some time ago to fit an LED light and run the cable for it to the old boot light and that was hard enough working on my knees (had to use a mirror to see what I was doing). If I had to remove the trim I think I'd fold the back seats and lie upside down. Trouble is I'm not getting any younger and might have serious issues getting out again!

Good luck with it - let us know how you get on.

 

[jenspp00]

@Jiggie I had exactly the same problem today, the roof is dead in closed position.

The roof reset procedure does not fix the problem.

Turns out that the problem is related to a faulty outside temperature sensor, which is located in the passenger side rear mirror.
We've had a problem with the temperature sensor for a while, all of a sudden it started giving crazy outside temperature readings - 60-70 degC, but this morning the reading is just "---".

When I open the side mirror (panel on the back of the mirror pops out) and pull out the connector which connects power to the side mirror adjustment and the temperature sensor, the roof works !!

Next step: replace the temperature sensor.

 

[Jiggie]

I ended up replacing the roof control module which fixed the roof but broke the boot which no longer opens. However I tried so many things (in replacing a wiring loom) that it could have been anything which stopped the boot from opening. Unfortunately the reset procedure doesn't make any difference

 

[Derbyfella]

Have you tested youve got volts to the boot switch?

 

[Jiggie]

Hi, yes I think it has got power, it just doesn't respond to anything any more