Hello, me and my parent are working on a used 2006 XC70 we recently acquired, trying to get it into out-of-province inspection shape. The high beams are not turning on, despite the rotary switch on the LSM being in the correct position (12 o'clock) when the vehicle is powered up, the dashboard high beam indicator lighting up, and the low beam angle adjustment working properly. We have so far done the following in the process of troubleshooting:
- replaced high beam bulbs, and checked that, despite wiring continuity, no voltage is sent to high beam sockets when activated
- verified circuit continuity to the CEM from the headlights, and both the SWM and LSM
- found circuit continuity between the SWM and LSM green/white wires (the colour listed in the wiring diagrams for high beam control), and confirmed both modules' power input wires are at 12V
- replaced the CEM with a remanufactured and cloned one from Xemodex (they told us the original had no detectable problem either)
- verified all other functions linked into the SWM (wipers, error message reading, steering wheel buttons) are working normally
- cleaned contact pads inside of the stalk switch
Despite all of this, the high beams still do not turn on. Our latest attempt is to get a brand new LSM and stalk switch, which we are waiting for. I was thinking it might also be a chip in the SWM, but I'm not sure whether the stalk switch circuits go into the SWM chips, or if they are just routed through the circuit board directly to the socket (after all, the SWM circuit board where the stalk plugs into it, and the output to CEM is green, while the rest of it is blue).
On a related note, a couple times when I attempted to flash the high beams to test, or covered the dashboard daylight sensor, the driver's side low beam would begin to flicker on and off, and finally turn off, until I powered off the car and restarted, at which time it would be on again.
Has anyone experienced a problem like this before? I will update when the LSM and stalk are replaced, but we'd like to get this thing over with as soon as possible, since we've already pumped $1000 extra bucks into it for effectively no reason. Also, does anyone know what the dash daylight sensor is officially called, and where we could buy a new one if needed?