12v but bulb and led won’t work!!!

[Garth124]

Ok so I’m utterly stumped here.

Parking light on passenger side is out so swapped the little bulb, no joy,
Found a thread saying it’s in series with the led light.
Bought a replacement unit, still neither light up……

Thought pattern was there must be no power but I’m getting 10v on one side and 0.9v on the other. What I don’t get is the 0.9v is the working side! So I’m guessing my meter had a bad connection

When I turn car on the non working side goes up to 12v

So the side that shows the higher voltage is not working.

I’ve never seen this before and can’t see how this is possible. ( I’ve swapped bulbs between sides to see if new one is faulty no luck

It can’t be an issues in the ecu can it??? Surely not

Feeling like I’m being utterly dumb here

[Garth124]

Update,
When I disconnect the bulb and led both connections have 10v
When the bulb is connected the led goes to zero
When the led is connected and the bulb is out the bulb volt goes to 1 v

Even more confused

I’ll try it with engine running

[Garth124]

With the engine running I have 1v at the light and zero at the LEd!

Found same side rear fog out so swapped it with the other side but that didn’t fix it

[Garth124]

Well if anyone else has this stupid issue, it’s fixed it’s self by disconnecting the battery while the lights were on and re connecting in less than a second.

[mm60103]

Originally Posted by Garth124

Well if anyone else has this stupid issue, it’s fixed it’s self by disconnecting the battery while the lights were on and re connecting in less than a second.

So not a Volvo but a Peugeot. It has an ECU but it also has a control board mixed up with the fuse box. They do die and they do terrible things. One side of the side lights would stop working. Surreal experience when a neighbour called to say the rear fog light was on. Nothing else was on, car locked and I was in the house. The lesson I learnt is that there is a company in the UK, BBA Reman who can repair these and many other other circuit boards. Well done if you have fixed it though. I've had good experience with BBA reman but there are plenty of others out there who I'm sure do a similar good job. As a p.s. they did repair the instrument cluster on my S80 when all of the pointers crashed to zero. Car drove fine but clearly wasn't going to get through the mot!