Technical Convertors socket- pin 11

[Jim Snell]

I am having some trouble solving a problem of the marker lights not turning off on my Aclass motorhome built on a ducato 2019.
I have read on previous posts that pin 11 on the convertors socket should become earthed when the headlights are on but not earthed when the headlights are off.
So if I put my multimeter between 11 and chassis on ohms the readings should vary between headlight on and headlight off? And if the reading is the same then the van is not sending the right signal to turn the markers off.
Please does this make sense and am I right or wrong?
Thanks Jim

 

[rayc]

I am sure that the lights on signal from Fiat is battery negative when lights are ON. I have modified my amber side marker lamps as they were originally fed from the Electroblock EBL 271 and the relay contacts had fused together meaning they were permanently on. [ incidentally this happened when it was at a Fiat garage for a recall and was due to the battery being disconnected / reconnected whilst the light switch was at On position - this is a known weakness of the Electroblock]

 

[Jim Snell]

Thanks Rayc,
My marker lights are not wired through the EBL 119. I have yet to find a relay to which they are connected.

 

[rayc]

Thanks Rayc,
My marker lights are not wired through the EBL 119. I have yet to find a relay to which they are connected.

I am sure that when you do you will find it is activated by the 'Fiat Lights On signal' which is a Battery Negative.
What Make/Model is the MH?

 

[Communicator]

I am having some trouble solving a problem of the marker lights not turning off on my Aclass motorhome built on a ducato 2019.
I have read on previous posts that pin 11 on the convertors socket should become earthed when the headlights are on but not earthed when the headlights are off.
So if I put my multimeter between 11 and chassis on ohms the readings should vary between headlight on and headlight off? And if the reading is the same then the van is not sending the right signal to turn the markers off.
Please does this make sense and am I right or wrong?
Thanks Jim

I can confirm @rayc 's information above as I have checked the information in the last 30 minutes, while replying to another thread.

If you unplug the 15 way connector, do the side marker lights go out? If yes, then your problem may be similar to that described by Rayc.

The signal is supplied by the body computer. I would be reluctant to connect a meter selected to ohms to any such output or input. The diode test is a safer alternative.

If you need to check the signal, use the voltage range with the meter positive connected to 12V, and the negative to pin 11. With sidelights ON expect to read slightly less (about 0.8V) than full battery battery voltage.

The signal is supplied by the body computer, at pin 1 of the lower LH 52 way connector on the cab fusebox, of which pin 1 is again the lower LH corner. Or at least it was on an x250 model.

 

[Jim Snell]

I am sure that when you do you will find it is activated by the 'Fiat Lights On signal' which is a Battery Negative.
What Make/Model is the MH?

Etrusco I 7400 2019

 

[Jim Snell]

I can confirm @rayc @s information above as I have checked the information in the last 30 minutes, while replying to another thread.

If you unplug the 15 way connector, do the side marker lights go out? If yes, then your problem may be similar to that described by Rayc.

The signal is supplied by the body computer. I would be reluctant to connect a meter selected to ohms to any such output or input. The diode test is a safer alternative.

If you need to check the signal, use the voltage range with the meter positive connected to 12V, and the negative to pin 11. With sidelights ON expect to read slightly less (about 0.8V) than full battery battery voltage.

The signal is supplied by the body computer, at pin 1 of the lower LH 52 way connector on the cab fusebox, of which pin 1 is again the lower LH corner. Or at least it was on an x250 model.

Thanks for your help. If I unplug the 15way connector the lights stay on. Voltage readings at pin 11 agree with your predictions.
Where next I wonder.
Jim

 

[rayc]

Thanks for your help. If I unplug the 15way connector the lights stay on. Voltage readings at pin 11 agree with your predictions.
Where next I wonder.
Jim

To the relay. In my working days I had a very cheap and easy audio signal generator that i would connect to the wire I was interested in and could follow the route with the associated audio tracer

 

[Communicator]

Thanks for your help. If I unplug the 15way connector the lights stay on. Voltage readings at pin 11 agree with your predictions.
Where next I wonder.
Jim

I respectfully suggest: Find the relay. Converters manual may help in the search.

 

[Jim Snell]

I have found the relay. Remove relay and lights go out. Use a substitute lights stay on.
How do we explain this?

 

[rayc]

I have found the relay. Remove relay and lights go out. Use a substitute lights stay on.
How do we explain this?

Something is activating the relay? With the relay removed what voltage do you get across the socket coil contacts when the lights are Off and On?

 

[Jim Snell]

Something is activating the relay? With the relay removed what voltage do you get across the socket coil contacts when the lights are Off and On?

12 volts in both situations

 

[Jim Snell]

12 volts in both situations

Between 86&85 also between 30&87

 

[rayc]

Between 86&85 also between 30&87

This is with the relay out? In response to my question "With the relay removed what voltage do you get across the socket coil contacts when the lights are Off and On?" you replied "12v in both situations" . Where is it getting the 0V from when lights are switched Off?

 

[Communicator]

If 12V across 85 & 86, with 15 way connector unplugged, may I suggest an earth fault on negative lead to the relay coil. From the Bosch notation this should be the wire connecting to 85. Terminals 30 & 87 are the relay contacts. With the relay removed, I would expect to see 12V across these socket terminals.

 

[Jim Snell]

This is with the relay out? In response to my question "With the relay removed what voltage do you get across the socket coil contacts when the lights are Off and On?" you replied "12v in both situations" . Where is it getting the 0V from when lights are switched Off?

This is with the relay out , and the 15 pin connected. 1/ headlights on. 2/headlights off.

 

[Jim Snell]

If 12V across 85 & 86, with 15 way connector unplugged, may I suggest an earth fault on negative lead to the relay coil. From the Bosch notation this should be the wire connecting to 85. Terminals 30 & 87 are the relay contacts. With the relay removed, I would expect to see 12V across these socket terminals.

This is with 15 way connected. Should I go and test with it disconnected?

 

[Communicator]

This is with 15 way connected. Should I go and test with it disconnected?

That would prove that the 0V signal at the relay is spurious, and probably represents a wiring fault.

 

[Jim Snell]

With 15 pin disconnected and relay removed tested at relay socket.
Headlights on (85/86) 12volt (30/87) 12volt
Headlights off (85/86) 12 volt (30/87) 12 volt

 

[rayc]

With 15 pin disconnected and relay removed tested at relay socket.
Headlights on (85/86) 12volt (30/87) 12volt
Headlights off (85/86) 12 volt (30/87) 12 volt

Communicator said "If 12V across 85 & 86, with 15 way connector unplugged, may I suggest an earth fault on negative lead to the relay coil."

You will have to determine where the 0V is coming from to give 12v on 85/86. [Lights on or off will have no effect with the 15 way disconnected.]