Side lights not working. Any ideas?

I have a 300 tdi with an odd problem.

I noticed the other day that the passenger side sidelights both front and rear were not working so starting at the front changed the little push in bulb but this didn't work.
Presuming I had a faulty bulb I tried another but this one didn't work.
Next I swapped the drivers side over and the proven bulb didn't work but the new one did, So eliminating that.
I also changed the rear bulb with the same result.
Checked all fuses, one by one including the ones in the engine bay and all are fine.

Can anyone suggest anything else I can check. I am not an electrician so don't know if they use a relay for each side, wouldn't have thought so on a low power circuit but you never know.

All other lights are working fine.

Until I solve the issue I am driving at night with the rear fogs on so I have a full set at the rear.

earthing? take bulb out use a multimeter and put earth on something u know will earth, and then test if your getting power atall, may help eliminate some potential problems

Cheers Ben.

I am confused as to why the front and rear are both effected, do you think they share the same earth?

Brian S said:

Cheers Ben.

I am confused as to why the front and rear are both effected, do you think they share the same earth?

Click to expand...

Tbh no idea, im in genve at the moment waiting for my flight home, can have a look on mine when i get back, it does seem pretty odd, think place to start would be to check earth and go from there, ohh thinking about it i belive rear light cluster is earthed with fuel pump, so that may not be the reason(only know this as when i cut my earth wire as fuel pump was ****ing out fuel when i was running on LPG, and did earth and back left cluster stopped working, so had to re earth and cut power to pump instead)! Good luck

Ill check it later when the missus gets home from work with the landy.

I'm sure each side is fused

The sidelights are fused, along with dip and high beams so six fuses in total, the passenger side glove box light shares the same fuse as the n/s side light, so is that working? it should if you have checked the fuse, if it is then you may have a problem with the light switch.

Glove box light works fine.

Will check the earths tomorrow.

Thanks for the input.

Brian S said:

Glove box light works fine.

Will check the earths tomorrow.

Thanks for the input.

Click to expand...

Although the earth is common through out the vehicle the pick up points aren't so you will be looking at two one for the front lamp the other for the rear . If there's an iffy earth at the front then the whole lamp will be out, ie. no main beam either.

So would the column switch cause this. Again very odd.

I have a spare switch to try tomorrow.

Brian S said:

So would the column switch cause this. Again very odd.

I have a spare switch to try tomorrow.

Click to expand...

Like any switch it can fail, but to find out you will need to test, you will need a diagram for the input and output wire colours plus a multimeter to find out.

If you getting 12v out from the fuse the next stop is at the switch input to see if it arrives there. May be an iffy connection loose plug and socket but you will need that diagram, there's one in the Haynes book.

Brian S said:

I have a 300 tdi with an odd problem.

I noticed the other day that the passenger side sidelights both front and rear were not working so starting at the front changed the little push in bulb but this didn't work.
Presuming I had a faulty bulb I tried another but this one didn't work.
Next I swapped the drivers side over and the proven bulb didn't work but the new one did, So eliminating that.
I also changed the rear bulb with the same result.
Checked all fuses, one by one including the ones in the engine bay and all are fine.

Can anyone suggest anything else I can check. I am not an electrician so don't know if they use a relay for each side, wouldn't have thought so on a low power circuit but you never know.

All other lights are working fine.

Until I solve the issue I am driving at night with the rear fogs on so I have a full set at the rear.

Click to expand...

Having the same problem, did you resolve this at the switch?

check inside fuse below steering wheel. fuse2 10amp rings a bell (could be wrong tho')
left and right sides are separate fuses.....
happened to me .......took fekkin ages to find the fault, traced it to a short in the wiring in the tail door behind the card.

Chrisw8 said:

check inside fuse below steering wheel. fuse2 10amp rings a bell (could be wrong tho')
left and right sides are separate fuses.....
happened to me .......took fekkin ages to find the fault, traced it to a short in the wiring in the tail door behind the card.

Click to expand...

Found it and solved it for mine.
The fuses tested good in and out of the circuit. Swapped bulbs to make sure they were not bad. Replaced 18 fuses that had anything to do with lights with fresh new ones anyway and all the lights (side and dash ) started working again.

Crazy luck

Blade type fuses aren't the most reliable on the market. Either the blade or the fuseholder socket starts to oxidise and you've lost your lights. You pull the fuse and test it and it shows OK, but then you push it back into the holder and it could be in the lap of the Gods whether the connection is good enough.

havent been about for a while and there will be a post for help from me soon lol but as for this issue a number of months back i had issues with my headlights that turned out to be the fuse box stripping it and cleaning it done the trick, however when it was all back in and test time i noticed the driver sidelight was out. after many bulb and fuse changes and chasing wires it turned out to be the actual bulb holder. snipped off the old one soldered then heat shrank the new one on and aint had an issue since.
good luck with it and if it turns out to be something else post it up for others to see