Hi everyone,

I have an octavia 1fl 1.9tdi (660.000km).

I recently have a bit of problem and would be really keen to avoid car service as I am in a foreign country.

 

The 4th 50A fuse next to the battery is burning out as long as I have relay 103 attached. Because of that I dont have front light, turning light, horn, windscreenwiper, and air ventillator. I do have rear and break lights, parking front light, innerlight, and radio. The car starts like charm also.

 

If I detach relay 103 the fuse is not burning out, but I still dont have electricity inside (frontlight,horn, windscreenwiper, airventillator).

 

The fuse is burning out once I start the car, for just giving it electricity it does not burn out, but still I have no electricity available.

 

I have measured relay 103 (trigerring the relay from the battery) and seemed to be working fine.

 

I checked and measured all the other fuses in the fuse box and relays (the ones with circuit diagram) and didnt find any fault.

 

I also tried to attach/detach the relays one by one and see which one burns out the fuse, but only relay 103 does that.

 

At this point I have really no idea what could I do.

 

Do you guys have any tip what could I check? 

Do you guys know what is relay 103 responsible for?

 

Thanks!

 

I forget to add, what I also tried

I have disconnected the related fuses from the fuse box (2, 12, 16, 18-27, 36 37, 40, 41), I have attached back all relays. But the 4th fuse next to the battery burned out again.

 

My idea was that perhaps one of the things that dont work (i.e. windscreenwiper) does it, so I disconnected them by removing their specific fuses. But it didnt help

Edited 11 January, 20251 yr by MatyasG

I tried one more thing, I have disconnected relay 103 and with a normal wire I connected the 2 legs between the switch. I expected the same behaviour so it is not the relay itself that causing the problem.

Update, I removed the plastic part from the wheel, and there is a connector unit which has a burned out cable. This cable goes to relay 103. Doesn anyone know why this cabel burned out? if I should replace the whole key whole unit and the cable, or something else?

Update: I have changed the burned out connector and the ignition switch next to it. After that the electrcity came back, but my glow plug was doing small lightbolts to the engine. I have removed the relay 103 so now no lighting is happining in the enigne (but i have no glow plug) Car still starts, and I have all features available

Not sure but think 103 is glow plug relay. It could be that the glowplug wiring is shorted or failed glow plug thats cause a short. On an old fiat van I had similar and it was the glow plug timer/control unit that had failed. Sorry not sure if the Octavia has one or where it might be.

Alasdair

Not sure if I am correct but I think the glowplugs are controlled/connected  via engine coolant sensor. If its unplugged or failed then they may be staying on for too long hence burnt out wire and blown fuse. Does the temp guage work?

Sorry cant be of more help

it might be the case that the glow plug stayed on. I also realized that the heating is way less strong then before. So could be that you are mentioning. The engine temprature gauge works, but  often falls below 90 (70-80).

 

I attach how the glow plug was missfunctionating after changing the connector:
I seems to me the the rubber holding of that unit is also broken. 

Edited 30 January, 20251 yr by MatyasG

I now understand what you mean by lightbolts. The sparks are either a short or bad connection. Continuous sparking would I think blow fuse or eventually burn out cable at a connector. It will need to be repaired. It could be the glowplug itself or perhaps the wiring that joins them has broken or insulation failed or both. I would replace the wwiring harness. I think you should be able to get a repair kit.

Alasdair

Thanks, I will do that!

But to be honesty what is this part responsible for? Disconnecting the relay 103 the lighting stopped (I guess it disconnected this whole part), but the car still starts nicely even if it is cold.

I assume 103 supplies power to the glowplugs. I have an old octavia that only has 2 working glowplugs. It starts very well when car is cold unless the weather is really cold and well below 0 degrees. In cold weather -5C- to -10C  sometimes runs rough for about 20secs then is fine. I need to replace them.

Alasdair

Okay, thanks for the info. I guess I can use it like that for now then, and replace it as I can

49 minutes ago, Alasdair1 said:

The sparks are either a short or bad connection.

 

The glowplug connectors have been removed from the two glowplugs visible in the video, probably all 4, the unshrouded connectors are laying on the engine block, the one sparking is shorting to earth being dragged over the engine block by the vibration, the effect on the video looks like a massive 100kv spark generator but in reality will be like the spark from disconnecting a battery being charged or discharged.

 

It will be that intermittent short circuit that has blown the fuse and melted the wiring, reconnect the glowplug connections, replace the fuse and all should be well unless the ovecurrent has welded the relay contacts together.

 

I'm surprised that me with my poor vision is the only one to have noticed this!

1 hour ago, Alasdair1 said:

I assume 103 supplies power to the glowplugs. I have an old octavia that only has 2 working glowplugs. It starts very well when car is cold unless the weather is really cold and well below 0 degrees. In cold weather -5C- to -10C  sometimes runs rough for about 20secs then is fine. I need to replace them.

Alasdair

Mine had a similar issue, and would fire in about 1s then idle roughly with lots of white smoke for about 10s, then be fine until the next cold start.