Seat Ibiza 6J rear stop light not working one side

[str1ng]

Hi all,

I have 2011 Seat Ibiza ST (6J8) 1.2 TDI, and I'm dealing with a rear left light issue.

The left rear brake light (stop light) and tail/position light don’t work — but the left turn signal on the same unit DOES work.
Meanwhile, the right rear light works perfectly.

I’ve already:
- Checked and swapped the P21/5W dual filament bulb – it’s fine
- Cleaned the socket – looks perfect
- Measured voltage on the connector:
➤ Pin 3 has no power
➤ But the turn signal wire still gets 12V and works as expected

Which tells me the ground is fine, the connector isn't dead, and the whole light unit isn't fried – but there's no feed to the brake or tail circuits on that side.

I suspect the wires running through the tailgate rubber boot may be broken (very common issue?)
Has anyone here dealt with a similar situation on an Ibiza ST (6J8)?
Looking for confirmation or advice before I start cutting into the wiring loom.

Thanks in advance!

 

[RUM4MO]

With the back hatch opened fully, try manipulating the rubber conduit just in case you can feel any "roughness" that would indicate broken wire(s). If you need to repair any wires, what I've done is, pull the two broken ends back ie one into the hatch and the other into the body so that you always make joins away from the area that gets flexed.

Touch wood, I've never had this issue with a VW Group car since being involved with 8 over the past 25 years - I did have this issue with a Ford though, and an old SAAB 9-5 my mate had.

One first thing that I would try, is to bolt a length of wire to a clean body bolt and touch the bared other end of it onto that stop/rear bulb body as a final "it's not an earth issue. I'd even do that using the hatch frame as earth and then the body frame as earth. Better to do too many obvious easy things before pulling/breaking almost good wiring. In an ideal world, I'd also do the same with a suitably fused +12V supply, I bought a "power probe" for my mate's big birthday to use for this sort of thing.

 

[str1ng]

With the back hatch opened fully, try manipulating the rubber conduit just in case you can feel any "roughness" that would indicate broken wire(s). If you need to repair any wires, what I've done is, pull the two broken ends back ie one into the hatch and the other into the body so that you always make joins away from the area that gets flexed.

Touch wood, I've never had this issue with a VW Group car since being involved with 8 over the past 25 years - I did have this issue with a Ford though, and an old SAAB 9-5 my mate had.

One first thing that I would try, is to bolt a length of wire to a clean body bolt and touch the bared other end of it onto that stop/rear bulb body as a final "it's not an earth issue. I'd even do that using the hatch frame as earth and then the body frame as earth. Better to do too many obvious easy things before pulling/breaking almost good wiring. In an ideal world, I'd also do the same with a suitably fused +12V supply, I bought a "power probe" for my mate's big birthday to use for this sort of thing.

Thanks a lot, I really appreciate the time and explanation!

I’ll be honest though — I’m not that experienced with car electrics, so I’m trying to make sure I fully understand what you meant.

From what I got: you're saying I should gently move the rubber conduit while the hatch is open, and feel for any weird stiffness that could point to a broken wire inside — and if I do find a break, then fix it away from the flexing area, so the repair doesn’t snap again over time?

Also, you mentioned testing the earth (ground) with a wire — is that just to rule out a bad ground connection?
Because in my case, the left indicator still works fine — only the tail and stop light are dead.
Does that mean the ground is likely OK, and the problem is more on the +12V side?

One more thing — my friend suggested just “borrowing” power from another light to get it working again. I’m not sure that’s a great idea, but I’d love to hear your opinion on that — good backup fix or asking for more trouble?

Thanks again!

 

[RUM4MO]

I was meaning just leave the rubber conduit in place, but squeeze it between your fingers.

I'm not totally up to date with how the rear indicators are operated, so just in case they have a solid +12V supply and the "earth" side is controlled by the car to operate the light or it is just the usual solid earth and the +12V supply that is controlled, I suggested applying another car frame and/or car hatch frame earth connection. Make sure that any working lights on that side are operating at the expected brightness, just in case it is an earth issue but the earth lead is partially fractured.

Tapping into the light on the other side is okay - but it should already to connected to that side, so ideally another check would be to check for continuity from that other side - but you would need a digital multi meter to do that, cheap ones don't cost much and can save you a lot of time and money going forward.

Frankly trying to sort out electrical issues without a multi meter is not a good idea, all down to luck.

Edit:- these cars can have horrible rear lamps connectors, basically bent bits of steel plated with something cheap and that can end up with the solder contacts on the actual bulbs being crushed/squashed - when these bulb holders used to be made from a lighter weight but more expensive spring steel or another similar metal, so only made correct positive contact with the bulbs and never ever crushed/squashed the solder contacts of the bulbs.

 

[str1ng]

Got it—thanks for the tips!