Problem - 2000 Volvo C70 Convertible Alarm

Hi All,

I thought I would post this on Oz Volvo as it may be Australian Model specific as ran out of ideas what my issue can be and i gather someone with a C70 or even a S70 / V70 may of had a similar issue.

When I got my C70 last year it had no remote only one spare key but the previous owner found 3 others (2 with chip 1 not)

These spare keys do not start the car and Volvo Can not program them.

I had a new 3 button remote programmed in hopes this will enable the alarm but it didn't. It locks the doors, indicators flash etc but no light on the dash as it does with my S40.

I did a lot of research with alarm options on the c70 and for the 2000 model there was really only 1 option the Horn siren and Alarm Relay (Volvo universal relay 9494424) I have checked all wiring and there is a harness on the left hand side just behind the corner indicator for the Siren Module. There is also a plug-in a blank for the Bonnet switch. The plug for the Alarm horn also was plugged into a blank. and the Alarm relay had a socket connection.

I have since bought a genuine relay and installed it along with a Horn on the rear firewall above the turbo.

I have also shorted the bonnet switch socket so it reads closed.

I have ran full diagnostics and everything appears fine. all switches work and say closed or open. I can test the LED dash light and it works. I can lock and unlock everything from my diagnostic tool. the only thing I cant do is activate an alarm or test siren/horn as nothing happens and don't get an error.

There is no error codes either. Fuses are ok.

Since I can see the Volvo lock and guard module and run tests etc and that it has all sensors including inclination etc basically the full alarm system. Why doesn't it activate?

Parts database says it just needs the alarm relay for the alarm to work, no mention about extra software.

Would anyone have an idea what it may be? I have a feeling since the relay was missing etc it may need to be activated by Vida for the alarm to work which i find is crazy as why bother with all the sensors for the alarm but not have it active?

Apart from that the car has been great, got it in top condition with a BSR Stage 1 tune and 3" exhaust and Snab / BSR intake.




  • Ex850RSnoopy @Ex850R Somewhere Over the Rainbow. Melbourne.

    Is that the car Mark had?

  • From what I can see from service history it was possibly owned by Hertz prestige Hire then one other owner. I got it with 146,000k on the iso and have done a fair bit to it since, front projector headlights, ceramic coating. Coilovers new head unit engine stuff silicon hoses. Turbo mods etc

  • jamesincJames @jamesinc Oz Volvo Ice Fortress

    @julesburg please make sure to make posts in the correct category, this category (Website) is only for info and questions about Oz Volvo itself. I'll move this post to the troubleshooting section for you.

  • Great thanks @jamesinc Im not sure how it ended here,

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