C70 convertible roof, how does it work?
 

I am currently touring the usa in a good looking 2004 C70.
Except for 2 inches of duck tape filling the gap between the rear roof panel and the boot lid.
On closing the roof the two rear tensioner got captured beneath the parcel shelf but didn't tension down the roof.
Now if you press the roof up button it just jiggles about. If you press the roof down button it just jiggles about.
Any suggestions how I get it out of this pickle?
These are magic till they no longer function!
Joined the forum because every volvo agent in west usa has a two month wait time.

I suspect the microswitches that operate the rear cover have broken. However, your best bet is to get on Facebook and search for Volvo C70 mark one roof problems and fixes. Paul Mountain is the chap who can advise and will talk you through what the problem is and how to resolve. Although Paul is UK based, he helps folks worldwide.

The roof is actually a very simple construction with 4 motors (rear latches, deck cover latch, main roof, front latches) and a similar number of microswitches and potentiometers (position sensors).

There is roof ECU which is a simple logic system, and there is a 7 (I think) step sequence to opening and closing the roof.

In 99% of cases, the problem is a switch, broken wire, or potentiometer that has become dislodged or broken, and the system cannot tell if one of the steps has completed or doesn't get a consistent/expected state.

Unfortunately, given the last of these cars were made 18 years ago, there are very few Volvo dealers with any mechanics that know anything about them, and although any fault codes from the roof ECU and sensor values can be read and cleared by VIDA, to test actuations and program new components in, VIDA's predecessor (VST2000) is required and they are near non-existent today. Hence they best way forward is to find an independent chap - and Paul Mountain is one such person - highly regarded on forums - but he does it as a hobby I think.

Anyhow back to your roof - you can manually close it if you can find the manual roof tools - there should be a cranked allen/Torx key and a T-bar tool.

- Open the boot and locate the two holes in the rear bulkhead to insert the tools, you need to lift up a flap of boot lining carpet to do that

- Insert the T-bar tool (widest leg) into right hand hole and turn anti-clockwise* as far as you can - you will hear a few clicks and clunks - this operates a gearbox so you can manually operate the roof, disconnecting one of the motors. You then turn it back just one click.

- Insert the torx end of the cranked handle into the left hand hole and turn clockwise whilst pushing down hard on the middle of the tension bow - this should draw the roof seal down onto the top of the deck and complete the closing cycle.

You will need to experiment - by very gentle - *I may have got my clockwise/anti-clockwise directions mixed up as it has been a few months since I have done this.

First task is finding the tools, usually they are in the pocket of the boot, spare wheel well or glovebox, sometimes in a tool wallet.

EDIT: Just found this - it may help : https://volvoforums.com/forum/volvo-...en-roof-69965/

Did you get it fixed? I have fixed three different problems on mine, and have amassed a lot of resources and experience in the process. I've got wiring diagrams, sequence diagrams etc if you need anything and any more advice.

I would quite like to import a reconditioned VST from the US and do some sort of shared ownership between UK C70 owners one here.

I've always managed to do what I've needed with just VIDA and a multimeter so far, but I hate the risk that some day I am going to need a VST and going to be stuck. Even if you can find a dealership that still has one they often seem to be broken or incomplete.

A member on here sent me the complete set of K-line codes for everything VST does with the roof controller. So it would be a really interesting project to make something home brew that could replace VST for roof controller duties, using something like https://github.com/handmade0octopus/ds2

It would be good if there was at least one working VST in the uk. I think part of my roof problem is it has had a new fabric roof fitted at some point that is slightly thicker than the original and it hasn’t been recalibrated for it.

Currently mine is not working again, I’m suspecting the rear latch microswitch(es) going to have a look later after having to spend the hottest weekend so far under cover :-(

If you've not got VIDA, you're very welcome to bring it over some to mine in Sheffield. Funnily enough I had to fix one of my microswitches yesterday. It had physically sheared off I think when I was hurriedly manually operating the roof. Was able to glue it back together. It's so nice to have the top down again and no infernal dinging noise.

Forgive my ignorance team, what's a VST?

It's an old dealership handheld diagnostic device from the 90s.

https://encrypted-tbn0.gstatic.com/i...XTpZQ&usqp=CAU

Its replacement VIDA (software) and DICE (the hardware interface VIDA works with) can do most things on a mk1 C70 including reading many of the values from the roof controller. However, there are some things that only VST can do.

Below is VIDA and on the left are the values it can read from the roof controller:

https://i.imgur.com/duJIqEk.jpeg

You can see all the additional mk1 C70 roof capabilities of VST here: https://www.volvoforums.org.uk/attac...9&d=1620575256

Thank you - that's a friendly gesture but I do have VIDA and I would probably get very green eyed over your own car........

I'll keep this thread posted at to my diagnosis, I wasn't bothering as I didn't think too many people were interested but it's good to speak with someone "in the know"....