2010 XC70 low beam headlight - In need of help

niceskier · Post by **niceskier** » 31 Dec 2019, 10:12

Hi folks, quick question that I am hoping you can help with.

We lost both low beam lights on our XC70; replaced with new bulbs, didnt resolve... as such I went looking for fuse. Manual shows location for high beam, fog lights etc. but nothing on fuse's for the low beams.... Any help you can provide?

Post by **RickHaleParker** » 31 Dec 2019, 11:30

There are no fuses for the Low beams. Low beams get their power directly from the CEM.
Are all the other lights working, marker, tail, turn .. ect?
Which headlights do you have, Halogen or Xenon?

niceskier · Post by **niceskier** » 01 Jan 2020, 10:54

Thanks... high beams are working, fogs are working, tails are working.... from what I can tell only the Lowbeams went out. Local volvo indy shop suggested disconnecting battery, and then clamping positive and negative cables together for a few min and then reconnecting. Im assuming it forces the computers, CEMs etc to reboot maybe?

niceskier · Post by **niceskier** » 01 Jan 2020, 10:55

Halogen's, replacement bulbs recommended at local Autoparts store are LEDs; my plan tomorrow when stores reopen is to return those and buy halogens and try again, followed by steps mentioned above.

Post by **RickHaleParker** » 01 Jan 2020, 14:45

niceskier wrote: 01 Jan 2020, 10:54 Local volvo indy shop suggested disconnecting battery, and then clamping positive and negative cables together for a few min and then reconnecting.

The above worked when Control modules used volatile memory, which loses it's data when power is lost, that was a long time ago.
Today's control modules use non-volatile memory, which retain their data when power is lost, like flash memory does.

Your best chance without Vida-DiCE is:

1. Turn the key off for 15 minutes.
2. Disconnect negative battery cable.
3. Turn key to POS II.
4. Reconnect negative battery cable.

This will force the control modules to reinitialize. Reinitialization might clear a software problem.

I suspect you have a problem in your Light Switch Module (LSM) or the programed parameters got changed, which could be corrected with Vida-DiCE.

Have you cycled the Light switch the positions to see if the low beam will come on?

niceskier · Post by **niceskier** » 01 Jan 2020, 16:02

yes tried many times to cycle light switch to no avail... No key, has FOB that goes into slot... how would this process work without a key

Post by **RickHaleParker** » 01 Jan 2020, 16:18

niceskier wrote: 01 Jan 2020, 16:02 yes tried many times to cycle light switch to no avail... No key, has FOB that goes into slot... how would this process work without a key

FOB removed = OFF.
FOB inserted but engine not started = POS II.

Post by **RickHaleParker** » 01 Jan 2020, 16:29