XC 70 2006 - Unusual Position Light Problem

psimmo · Post by **psimmo** » 07 Jan 2015, 12:57

Upon turning the car on both rear offside position lights flash then immediately go out and stay out.
Bulbs OK, checked and changed, fuse OK, checked and changed. Power must get there and contacts must be OK to make them flash. All other position lights OK, all other bulbs in this cluster OK apart from the little LEDs which show no signs of life at all. Main agents were confused. The car informs me that I have a problem with a position light!
Suspect either the rear fuseboard unit, or the trailer unit (Volvo fitted for the towbar) that is wired into the circuit, or the wiring across the rear of the car from the rear fuseboard tho the light cluster...but just guessing. Anyone met this before?

Post by **chrism** » 07 Jan 2015, 16:05

I would be inclined to disconnect the trailer wiring and see what affect that has. If nothing else, get the P/N off of it and check with a dealer to see if it's even the correct one for your car. If it's aftermarket then I'd REALLY be suspicious.

Post by **jimmy57** » 07 Jan 2015, 20:44

The 2005 and later use transistor controlled circuits (replacing relays) and the circuit is monitored for current draw. It will shut down if the current is out of line. The LED strip could be the high draw.

You can read out fault codes from the REM and see what it says there.

psimmo · Post by **psimmo** » 08 Jan 2015, 07:19

Thanks for that info (re: auto shutdown of circuit due to a short being detected).
After a bit of a struggle managed to remove the light cluster and discovered the LEDs circuit board was wet. Dried it out and lo! Lights! Both position lights came back to life.
Can't say the same for the LEDs though. Looks like its the end of the line for them. No doubt expensive to replace. However, that's as good a result as I could have hoped for.
Can't see where the water gained access though but a bit of silicon should sort that.
What a good idea this site is.