V70: Electrical Bonnet catch switch replacement options?

[Stu B]

Hi All,

Just after it's first MOT in my ownership last week, my 2009 V70 developed the 'bonnet is open' warning issue, even when the bonnet is closed. I did some reading on her and found it related to the drivers side (UK) catch and a likely bunged up switch in there.

I've since lubricated it via various sprays and worked the catch back and to with a screwdriver which has occasionally removed the warning for a few seconds, then it returns. I wasn't too concerned but it also sets the alarm off, 7:30am yesterday being the latest occurrence, so I did a bit more troubleshooting.

Disconnecting the wiring to the catch here:




Using a multimeter I tested continuity between the pins going to the switch (right connector on the photo) and found they are open circuit regardless of if I close the catch with a screwdriver to simulate the bonnet being closed. As such, I think the microswitch in there is dead and needs replacing? Unless anyone else has other ideas? Could it have been dislodged by an over zealous MOT tester bonnet slam? I'm not sure what the mechanism looks like under the slam panel yet as it's a pain to get to.

I've seen reference on here to replacing the microswitch rather than the full catch (I'm a dab hand with a soldering iron) so wanted to see if anyone could point me to where to order the correct switch before dismantling the front of the car to find it?

For now, I have have bridged the connections in the plug (left connector on the photo) and insulated it to resolve the warning and allow the alarm to be set and not go off randomly. The car locks properly now with a flash of the indicators.

Ideas appreciated, it looks rather involved to remove the front grille etc. to get at it so I'd rather not do it multiple times!

Cheers
Stu

[Tatsfield]

Like you I also had that problem and it is documented in https://www.volvoforums.org.uk/showthread.php?t=279884. In my case the switch freed itself after lubricating with WD40 High Performance but it was only after a couple of weeks while I was driving around with the jumper in place in the connector. Fingers crossed, it's been two years now and the fault has not returned. I suspect that it wasn't a true electrical fault but rather a mechanical seizing of the switch operating arm. Since you can live with this work around, try repeated lubrication and checking by reconnecting at weekly intervals. It won't cost you anything more than a few sprays of penetrant.

[elzorillo]

Did shorting the connector not cause any issues or blown fuses? I disconnected and ran a meter across it and there's 12v dc on it so I'm loath to short it in case I blow something.

[Tatsfield]

The jumper merely replicated what the switch did in a closed position. There are no electronics involved with the switching, just a make or break across the power supply which the jumper duplicated as a temporary way of stopping the warnings and alarm malfunction.

[Stu B]

Hi, no issues - the connector has been bridged for just over a year now