Reverse lights not working on octavia 2 (switch, bulb and fuse are OK)

[tudi23]

Hello! I recently bought an Octavia 2 from 2008 and I noticed that the reverse lights of the car (both of them) are not working at all. First I checked the bulbs, second the related fuse, which is together with AC (as I remeber), but all of them were working just fine. Then I surfed on internet and I realised that it might be a faulty switch on the gear box. Today I checked that switch and the problem wasn`t there. The continuity test was a succes. Further I tried to short-circuit the cables with a paperclip and nothing happened, the lights aren`t working.  At the moment I think the problem might be a broken wire or a relay on the On-board Unit. Could someone give me some suggestion how can I check the cables or the module. I really want to fix this problem. Thanks in advance for the support!

[langers2k]

Any fault codes?

 

You could try some output tests or measuring values to check the wiring.

[tudi23]

There are no error lights or messages on board, only the fact that the reverse lights aren`t turning on. I wish to check the wires starting from the switch but I can`t find the final destination, nor the way through. Do you have any electrical schematics from this car? ....or any other ideas in order to be able to check the wires?

[Breezy_Pete]

What year is the car?

[tudi23]

1 hour ago, Wino said:

What year is the car?

 

Year: 2008

Engine: 1.9 TDI, 105 hp (77kW)

[Frenchtone]

bulb contacts in the holders ok?

[Breezy_Pete]

The switch seems to take ignition 12V into pin 16 of the 52 way connector of the onboard supply control unit (black/blue wire). See if you can read 12V there with ignition on and reverse gear selected.

The lamps are powered directly from pin 28 of the same connector.

[tudi23]

14 minutes ago, Wino said:

The switch seems to take ignition 12V into pin 16 of the 52 way connector of the onboard supply control unit (black/blue wire). See if you can read 12V there with ignition on and reverse gear selected.

The lamps are powered directly from pin 28 of the same connector.

 

I went to the car but unfortunately I couldn`t find the "52 way connector" on the control unit. Do you have any schematics or suggestive photos?  Thx

 

[Breezy_Pete]

Sorry was looking at Superb 2 info by mistake. Out now so can't help for a while.

[langers2k]

You can access all the wiring diagrams for you car here: http://erwin.skoda-auto.cz

 

There is a small fee but if you use a print to PDF function, you can keep the info

[wiilydog]

Have you followed the wiring from the switch connector plug as you probably find it is wire is broken not far from the plug but you need to pull back the plastic that protects the wiring from the heat to check.

[Breezy_Pete]

Try these pin numbers instead.

Switch to J519 onboard PS control unit, blue/black wire to pin 6 of a black 8-way connector.

Left reverse light from pin 12 of a brown 12-way connector, black/blue wire.

Right reverse light from pin 1 of a black 12-way connector, black/yellow wire.

[tudi23]

9 hours ago, Wino said:

Try these pin numbers instead.

Switch to J519 onboard PS control unit, blue/black wire to pin 6 of a black 8-way connector.

Left reverse light from pin 12 of a brown 12-way connector, black/blue wire.

Right reverse light from pin 1 of a black 12-way connector, black/yellow wire.

 

Yeah, I found those wires between the switch and the control unit, thx. One of them was totally broken (the black/yellow one). As you can see in the attached photo it`s only the plastic insulation who mantains the wire together. The copper is completely oxidated, which means that the reverse lights weren`t working for years.  Finally I repaired the broken wire and everything was working just fine. PROBLEM SOLVED! Many thanks for the support.

[Breezy_Pete]

To affect both lights, that must be the ignition 12V feed to the switch. The only wire I didn't discuss, because I guessed you would have already checked that the switch was getting power.

Glad to hear it's all good now.

Edited 30 July, 2018 by Wino