Flash light/button on steering wheel not working
Discussion
Already found some reasons for electrical functions which were not working. I have 3 to go. Washer button, Flash button and hazard.
The routing of the washer button seems relatively clear. It is the blue/yellow wire which comes out of the connector of the steering ECU. Not sure why there is no signal coming out of it.
Hazard is seperately wired with a connector on the pcb on top of the steering column.
What I do not understand is how the flash button is wired. If the lights are not on, you can flash with this button. If lights are on you ca switch from dipped beam to main beam.
Can someone tell me how this is wired? And... the high beam? How do you normally switch this one on? It has been quite some time since I drove the car.
The routing of the washer button seems relatively clear. It is the blue/yellow wire which comes out of the connector of the steering ECU. Not sure why there is no signal coming out of it.
Hazard is seperately wired with a connector on the pcb on top of the steering column.
What I do not understand is how the flash button is wired. If the lights are not on, you can flash with this button. If lights are on you ca switch from dipped beam to main beam.
Can someone tell me how this is wired? And... the high beam? How do you normally switch this one on? It has been quite some time since I drove the car.
Yes, I turned the 5 ribbon cable on the steering ecu on one side. Suddenly dipped and main beam worked and also fog. So this cable should be in the right position now.
I found the cause for hazard. The 2 wires (green and yellow) are broken off the connector which is mounted on top of the steering colomn. I only hope I can fix the connector. I do not know where to get new ones.
I found the cause for hazard. The 2 wires (green and yellow) are broken off the connector which is mounted on top of the steering colomn. I only hope I can fix the connector. I do not know where to get new ones.
All of the Steering Wheel Function Control Unit outputs are Ground (GND) driven, which means they are floating when not active, and then when the steering wheel button is pressed pin 10 on the 10 Pin Ribbon (GND) is connected to the relevant output for the button
In your case the Washer Input in pin 2 on the 10 Pin Ribbon so you should be able to test that going to GND on being pressed and then this sending B8 on the output 18 pin plug to GND to trigger the Wiper / Washer Control Unit
The 4 buttons are Wiper, Wash, Horn and Dip / Main so I think the Flash is run differently, and the Stalk on the wiring diagram only shows indicators and hazards - this is the schematic which is a good reference
http://tvr-cerbera.co.uk/WorkshopWiringDiagrams/St...
HTH and any questions feel free to ask as I spent a while repairing mine so might be able to remember / help
In your case the Washer Input in pin 2 on the 10 Pin Ribbon so you should be able to test that going to GND on being pressed and then this sending B8 on the output 18 pin plug to GND to trigger the Wiper / Washer Control Unit
The 4 buttons are Wiper, Wash, Horn and Dip / Main so I think the Flash is run differently, and the Stalk on the wiring diagram only shows indicators and hazards - this is the schematic which is a good reference
http://tvr-cerbera.co.uk/WorkshopWiringDiagrams/St...
HTH and any questions feel free to ask as I spent a while repairing mine so might be able to remember / help
Juddder said:
The 4 buttons are Wiper, Wash, Horn and Dip / Main so I think the Flash is run differently, and the Stalk on the wiring diagram only shows indicators and hazards - this is the schematic which is a good reference
http://tvr-cerbera.co.uk/WorkshopWiringDiagrams/St...
Just thinking about it, I wonder if the original schematic is wrong and pin 3 on the 5 pin connector is actually the Flash as I can't see any reason to have two Hazard functions and it would make sense that the Flash was triggered by pulling the right hand stalk leverhttp://tvr-cerbera.co.uk/WorkshopWiringDiagrams/St...
This would then trigger the Steering Wheel Function Control Unit which could then just momentarily ground A7 on the output which is Main Beam Signal which would make sense
We can test this by connecting a multimeter to pin 10 GND of the 10 pin connector and pin 3 of the 5 pin connector and seeing if we get connectivity on pulling the RH stalk lever and then testing output A7 similarly...
Got the steering wheel off. Tested connectors in the steering wheel boss with ground. So, now the flash works. Problem was in the steering wheel button of the flash. One of the wires was loose.
Repaired my hazard wire. Works also.
I had the horn working, but now it sounds like it makes an attempt to blow the horn but then it is gone. I think it is also a contact. I had it working, so it must not be that hard to find.
What stays is the washer/wiper. So, when I push the button only the wiper goes off. No signal to the washer motor. The button is a combined ground for both functions. So, it has to go in seperate ways somewhere. This one will be the hardest to solve, because it was also a malfunction before I took the car apart.
Repaired my hazard wire. Works also.
I had the horn working, but now it sounds like it makes an attempt to blow the horn but then it is gone. I think it is also a contact. I had it working, so it must not be that hard to find.
What stays is the washer/wiper. So, when I push the button only the wiper goes off. No signal to the washer motor. The button is a combined ground for both functions. So, it has to go in seperate ways somewhere. This one will be the hardest to solve, because it was also a malfunction before I took the car apart.
flyingdutchie said:
Good information. I already found information in the workshop manual. It's a pity that the wiring diagrams are so unclear..... even when printed out some are unreadable....
We have some decent ones...http://tvr-cerbera.co.uk/wiringdiagrams.html
okay..... I hope someone can give me a hint or 2 on the washer function...... On 1 component it will be difficult for you to comment. My wiper control unit has been modified because I have a Volkswagen Golf wipermotor on the car (to get rid of the Lucas one).The steering ECU is not modified. I think, however that the modifier did not change much to the way the washer has to be engaged. There are 2 wires, both blue/yellow, on the wiper ecu. One wire is the input/signal coming from the steering ecu. The other one is the drive. If I put 12V on the drive, the washermotor starts.
What bothers me is that, when I put GND on pin 2 of the steering ecu, the wiperfunction of the wash/wipe does start and stop again when I put the GND off.
To my opinion I should also measure a 12V on the blue/yellow wire which goes from the steering ecu to the wiper ecu when I engage wash/wipe. I did pull the terminal from the connector (the washer signal which comes from the steering ecu). No 12V on the wire when I push the steering button or when putting ground on pin 2 of the steering ecu.
What does happen en is that the wiper control unit puts 12V on the wash signal wire when I switch on ignition. And naturally I measure also 12V on the blue/yellow wire on the steering ecu. So, the 12V on that wire is coming from the wiper ecu towards the steering ecu.
Can someone confirm my believings:
1. There should be a 12V on the blue/yellow wire on the steering ecu when the wash/wipe button on the steering wheel. This signal should also go away
when wash/wipe is stopped.
2. It is wrong to have a constant 12V reading on the washer signal/input wire on the wiper control unit (which comes from the wiper control unit in some
way)
What bothers me is that, when I put GND on pin 2 of the steering ecu, the wiperfunction of the wash/wipe does start and stop again when I put the GND off.
To my opinion I should also measure a 12V on the blue/yellow wire which goes from the steering ecu to the wiper ecu when I engage wash/wipe. I did pull the terminal from the connector (the washer signal which comes from the steering ecu). No 12V on the wire when I push the steering button or when putting ground on pin 2 of the steering ecu.
What does happen en is that the wiper control unit puts 12V on the wash signal wire when I switch on ignition. And naturally I measure also 12V on the blue/yellow wire on the steering ecu. So, the 12V on that wire is coming from the wiper ecu towards the steering ecu.
Can someone confirm my believings:
1. There should be a 12V on the blue/yellow wire on the steering ecu when the wash/wipe button on the steering wheel. This signal should also go away
when wash/wipe is stopped.
2. It is wrong to have a constant 12V reading on the washer signal/input wire on the wiper control unit (which comes from the wiper control unit in some
way)
flyingdutchie said:
okay..... I hope someone can give me a hint or 2 on the washer function...... On 1 component it will be difficult for you to comment. My wiper control unit has been modified because I have a Volkswagen Golf wipermotor on the car (to get rid of the Lucas one).The steering ECU is not modified. I think, however that the modifier did not change much to the way the washer has to be engaged. There are 2 wires, both blue/yellow, on the wiper ecu. One wire is the input/signal coming from the steering ecu. The other one is the drive. If I put 12V on the drive, the washermotor starts.
What bothers me is that, when I put GND on pin 2 of the steering ecu, the wiperfunction of the wash/wipe does start and stop again when I put the GND off.
To my opinion I should also measure a 12V on the blue/yellow wire which goes from the steering ecu to the wiper ecu when I engage wash/wipe. I did pull the terminal from the connector (the washer signal which comes from the steering ecu). No 12V on the wire when I push the steering button or when putting ground on pin 2 of the steering ecu.
What does happen en is that the wiper control unit puts 12V on the wash signal wire when I switch on ignition. And naturally I measure also 12V on the blue/yellow wire on the steering ecu. So, the 12V on that wire is coming from the wiper ecu towards the steering ecu.
Can someone confirm my believings:
1. There should be a 12V on the blue/yellow wire on the steering ecu when the wash/wipe button on the steering wheel. This signal should also go away
when wash/wipe is stopped.
2. It is wrong to have a constant 12V reading on the washer signal/input wire on the wiper control unit (which comes from the wiper control unit in some
way)
Have you checked the wiper control box in the passenger seat foot well. I believe it is this box that triggers the washer pump to operate.What bothers me is that, when I put GND on pin 2 of the steering ecu, the wiperfunction of the wash/wipe does start and stop again when I put the GND off.
To my opinion I should also measure a 12V on the blue/yellow wire which goes from the steering ecu to the wiper ecu when I engage wash/wipe. I did pull the terminal from the connector (the washer signal which comes from the steering ecu). No 12V on the wire when I push the steering button or when putting ground on pin 2 of the steering ecu.
What does happen en is that the wiper control unit puts 12V on the wash signal wire when I switch on ignition. And naturally I measure also 12V on the blue/yellow wire on the steering ecu. So, the 12V on that wire is coming from the wiper ecu towards the steering ecu.
Can someone confirm my believings:
1. There should be a 12V on the blue/yellow wire on the steering ecu when the wash/wipe button on the steering wheel. This signal should also go away
when wash/wipe is stopped.
2. It is wrong to have a constant 12V reading on the washer signal/input wire on the wiper control unit (which comes from the wiper control unit in some
way)
Your repleacement wiper control unit may not be correctly completing this function.
There is nothing wrong with th eLucas wiper motor it is just poorly placed in the Cerbera suffering water ingress but cleaning and regular cleaning keeps it working perfectly well.
Edited by gruffalo on Thursday 24th August 17:13
I did spend 600 pounds on the Lucas wipermotor. It did wreck the plastic gearwheel and burned out. I still have a new motor somewhere.....
Anyway.....you're right. The wiper ecu does drive the washer. Yesterday I measured everything up to get a picture of how it should function. I was hoping to find the cause of the malfunction. The question is..... how ist it driven. I have anoriginal-modified wiper ecu. I opened it up yesterday and looked at the pcb inside. It did not look like it had any modifications on the pcb. The wiring going to the modified wiper ecu is new (other colours). Except for the washer wires.
So, like on the original one there are 2 blue/yellow wires on the wiper control unit. One of them comes from the steering ecu unit underneath. The other blue/yellow wire on the wiper ecu powers the washer motor. So, something inside the wiper ecu should send 12V to this wire. This wire is not producing 12V and therefore the washer motor doesn't work.
It is an assumption that the modifier did not change the wiring on the washer function on the wiper control unit. I know. But why would he change that?
I need to understand what the blue/yellow wire is supposed to do when you push the (GND) washer/wiper button on the steering wheel. What is it what I should measure on the blue/yellow wire on the steering control ecu connector which is on the drivers side underneath the dash. Now it gets a constant 12V coming from the wiper control unit. This seems unlogical to me.
If I know what I should measure on this blue/yellow wire, when pushing and releasing the wash/wipe button on the steering wheel, I know if my steering control ecu is oke or not. If I put GND directly on pin 2 of the steering wheel control unit, the wiper function comes on but not the washer. That should rule out a faulty ribbon cable. And if I know if the wiper control ecu should send a constant 12V to the steering control ecu, I know if something is not routed the right way in the wiper control unit/connector.
I cannot ask you to commend on my modified wiper ecu, but it would help to know how the original function/connection should work.
Anyway.....you're right. The wiper ecu does drive the washer. Yesterday I measured everything up to get a picture of how it should function. I was hoping to find the cause of the malfunction. The question is..... how ist it driven. I have anoriginal-modified wiper ecu. I opened it up yesterday and looked at the pcb inside. It did not look like it had any modifications on the pcb. The wiring going to the modified wiper ecu is new (other colours). Except for the washer wires.
So, like on the original one there are 2 blue/yellow wires on the wiper control unit. One of them comes from the steering ecu unit underneath. The other blue/yellow wire on the wiper ecu powers the washer motor. So, something inside the wiper ecu should send 12V to this wire. This wire is not producing 12V and therefore the washer motor doesn't work.
It is an assumption that the modifier did not change the wiring on the washer function on the wiper control unit. I know. But why would he change that?
I need to understand what the blue/yellow wire is supposed to do when you push the (GND) washer/wiper button on the steering wheel. What is it what I should measure on the blue/yellow wire on the steering control ecu connector which is on the drivers side underneath the dash. Now it gets a constant 12V coming from the wiper control unit. This seems unlogical to me.
If I know what I should measure on this blue/yellow wire, when pushing and releasing the wash/wipe button on the steering wheel, I know if my steering control ecu is oke or not. If I put GND directly on pin 2 of the steering wheel control unit, the wiper function comes on but not the washer. That should rule out a faulty ribbon cable. And if I know if the wiper control ecu should send a constant 12V to the steering control ecu, I know if something is not routed the right way in the wiper control unit/connector.
I cannot ask you to commend on my modified wiper ecu, but it would help to know how the original function/connection should work.
There is a possibility that the 12 volts that's present at the wash button is a 12 volts supply to a relay coil within the wiper control unit
If the above is proven to be the case, there's a washer motor relay in the wiper control unit that has a supply to its coil when the ignition is switched on, sending a negative to the other end of the relay coil when pressing the wash button will activate the relay which should then switch a supply to the washer motor through its contacts
The above is a guess
If you were to post some images of the control unit pcb and its components plus where it's located there would be a better chance of someone solving the problem
If the above is proven to be the case, there's a washer motor relay in the wiper control unit that has a supply to its coil when the ignition is switched on, sending a negative to the other end of the relay coil when pressing the wash button will activate the relay which should then switch a supply to the washer motor through its contacts
The above is a guess
If you were to post some images of the control unit pcb and its components plus where it's located there would be a better chance of someone solving the problem
The first 2 pics (see replies below) are from the steering ecu (casing off). The other 2 are from my wiper control unit.
Like Judder said, there is no 12V running through the buttons on the steering wheel. When you push the steering wheel button it makes ground, through the ribbon marked with 'O". In case of the washer/wiper on pin 2 (second from left) on the steering control unit. You can test the wash/wiper also by utting ground directly on this pin 2. In my case only the wiper works. No washer. On the second picture of the steering control unit there is a blue/yellow wire on the connector. Second from right. This one gets a constant 12V from the wiper control unit, which seemd odd to me. This wire is the washer input, as can be seen on judders drawing.
The last 2 pics show the wiper control unit. I did get my hands on a picture from the connector from somebody else's Cerbera. The wiring does look rather like the original. This wiper control unit has been modified because of my Volkswagen Golf wiper motor. There are 2 blue/yellow wires on this wiper control unit. On position A9 and B9. Above eachother. One of these is the same wire as on the steering control unit and the other goes to the washer motor.
So, going back to my questions..... is it correct that the blue/yellow wire between steering control unit and wiper control unit should have a constant 12V when ignition is on? The other one is how the blue/yellow wire on the wiper control unit has to get it's 12V?
Edited by flyingdutchie on Sunday 27th August 13:23
Gassing Station | Cerbera | Top of Page | What's New | My Stuff