On a 2004 TDI Octavia what relays are fitted.

Thanks.

It depends on the engine code/gearbox code/year/trim level/options.

What problem do you have?

Assuming 2004 ASZ...

2/3 - Bulb failure control unit

4 - Headlight washer system relay

5 - Right seat heating relay

6 - Left seat heating relay

7/8 - MF steering wheel control unit

10 - Lift pump relay

11 - Dipped headlight control unit, on/off

12 - Diesel direct injection system relay

13 - Radiator fan run-on relay

1 - Horn relay

2 - X contact relief relay

3 - Illumination level control unit

4 - Glow plug relay

V/VI - Intermittent wipe/wash relay

The problem I have is when I connect my trailer socket to the car the following happens

(1)

Indicators work both on car & trailer , but on trailer the fog light seems flash dimly also

(2) Indicators and tail lights on car and trailer work but again the fog light on the trailer tent flashes dimly

(3) When fog lights are on in the car. The high level brake light on the car comes on and then the trailer light just glow with no indicators working. Also as the fog lights are turned on the indicators click quickly.

I would of dismissed the car at being at possibly being at all at fault until the high level brake light came on dimly. Cat has dedicated trailer wiring and has been fitted with genuine skoda reversing sensors.

Thanks.

You have a bad ground on the trailer

+1 check the earth's or take the trailer lights apart to check for corrosion on the bulb holders

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Yup. 3rd-ed.

Just to update have now had a separate trailer board connected up and the lights on that went crazy with the brake lights flashing etc.

Look where the wiring enters the boot and follow it till you find the ground, that should be your problem

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Also, check the connections in the socket itself.

Also, check the connections in the socket itself.

+1 . I have had this too. The wires corrode inside the connection point in the socket. While I had it apart I stripped back all the wires and remade the connections, putting Vaseline in the socket part first to stop future problems. My trailer used to sit a field most of the year.

+1 . I have had this too. The wires corrode inside the connection point in the socket. While I had it apart I stripped back all the wires and remade the connections, putting Vaseline in the socket part first to stop future problems. My trailer used to sit a field most of the year.

Fitted a new trailer socket, it seems the fault is on the towbar socket as another trailer board lights went all funny.

Fitted a new trailer socket, it seems the fault is on the towbar socket as another trailer board lights went all funny.

There was a line missing from my post which should read "My trailer used to sit a field most of the year but it was the vehicle socket that had corrosion (salt?). I guess you changed the plug on the trailer cable. It is the fixed socket on the car you need to check.