I found the culprit. I was on the verge of going to the dealer, but I thought I'd try one more thing: I'd swapped the four unlocking relays for others that weren't causing problems and that didn't help, but this time I bought 4 brand new ones and swapped them in, one at a time. Turned out that the t...

The central locking button on both the driver and the passenger front doors of my 2002 XC70 will lock but not unlock the doors and tailgate, unless the driver’s door is open. Then it sometimes unlocks, sometimes not. The remote unlocks everything just fine, and, the key itself, used manually, will u...