horn, main beam and sidelights, what do they have in common?

[markh1]

When the car got to the MOT station the above were not working. I have checked fuses and the switches seem to be ok.

Has anyone got any suggestion as to what the problems might be?

Thanks,
mark

[Dave 500]

Check the ribbon behind the steering wheel they some time come loose. Do your wipers work?

[markh1]

Yeah the wipers work. It is a bit of an anomaly because if it was something to do with the steering wheel then I don't know how it would affect the sidelights?

The ribbon cable seems ok but I will try it again.

[Boosted Cerb]

Worth checking the earth bolt under the F1 panel on the drivers side front upright. Got a feeling all those things you listed have a common earth.

Rich.

[markh1]

thanks rich i will have a look.

[markh1]

The earths seem fine but now the wipers are not working??

Oh how I hate electrics!!

[gcpeters]

Sounds like the ribbon cable is round the wrong way

try taking it off and swapping the ends round

also check the connection of the switches onto the steering wheel hub

with regards to the side lights i bet its the ribbon cable going to the switch/control box

and also, here is my post and it contains lots of pics to help you out

http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

Enjoy!

Edited by gcpeters on Sunday 28th March 14:23

Edited by gcpeters on Sunday 28th March 14:23

Edited by gcpeters on Sunday 28th March 14:24

[markh1]

The wipers have only stopped working since I took the wheel of to check the connections so it must be something to do with the wheel or the connections around it.

How did you get the steering wheel boss off past the aluminium housing for the two lower dials? to expose that strip of circuit board that the steering wheel buttons plug into?

[gcpeters]

Hi Mark

if you mean the ECU strip like in my picture where the 4 connectors plug into it im afraid you cant with out de soldering the circuit!

if you mean where the ribbon cable wraps round and then plugs into the boss ( bottom of the wheel) it is just glued in and is simply a male version and extend the cable to the Steering Wheel ECU

what i did was take the wheel off, then plug it directly into the steering wheel ECU. Also one thing that is amazing usefull for testing are a set of these..

http://images.google.co.uk/imgres?imgurl=http://ww...

you can get them from maplins, it lets you test all the switches as you can connect them up a to a meter, and also you can put them direct into the ribbon cable/ pin outs and test (if you get my drift)

to test the wipers, its Pin 5 and then pin 1, 2 or 3, 4 (pin5 = live, pin 1 - 4 = buttons)

GP

[markh1]

I have just plugged the ribon cable from the ECU straight into the back of the steering wheel boss but it still does not seem to work.

When you say pin 5 is live, are you talking about the pins that go into the 4 plugs from the steering wheel? And if so are you counting five from the pin that is furthest from the steering wheel boss? Each of the four plugs from the steering wheel go onto 2 pins and I don't see how they work with just one of those pins being live, as all the switches on the wheel are wired separately.

Thanks,

[FarmyardPants]

Does the steering wheel have to be on the car for the wipers to work (does the wheel make electrical contact with the hub?) Just a thought in case you're trying with it off.

Re the original question, they are all at the front of the car! Could check for an earth somewhere near the horn?

[gcpeters]

markh1 said:

I have just plugged the ribon cable from the ECU straight into the back of the steering wheel boss but it still does not seem to work.

When you say pin 5 is live, are you talking about the pins that go into the 4 plugs from the steering wheel? And if so are you counting five from the pin that is furthest from the steering wheel boss? Each of the four plugs from the steering wheel go onto 2 pins and I don't see how they work with just one of those pins being live, as all the switches on the wheel are wired separately.

Thanks,

yes this confused me as well until i found the wiring diagram

the horn, lights, wash and whipers plug in one side the little PCB board in the steering wheel...
The pcb board goes through the boss, and then the ribbon plugs in the other side

the pcb basically just routes the connections to the ribbon cable

horn - Live goes to pin 5 ribbon, other goes to pin 4 ribbon end
lights - live goes to pin 5 ribbon, other goes to pin 2 ribbon end
whipers - live goes to pin 5 ribbon, other goes to pin 1 ribbon end
wash live - goes to pin 5 ribbon, other goes to pin 3 ribbon end

so if you join up pin5 to any of the pins 1 - 4 it makes the circuit

i had the problem where the circuit was broke on the little PCB, as you can see from my pics, so i wired in a bypass cable (check the post for the pics)

you are affectively bypassing this and now going direct to the sterring wheel ecu (again the smaller on with indicator cancelation disk) and that then goes to the large sterring wheel ECU box

are the ribbons round the correct way on both of these? you have to go through the steering wheel ECU first, and then to the larger box as it wont work other wise !

secondly, do any of the other buttons work? if so then swap what ever is working to the other slot, ie put the wipers button onto the wash (again see my pics) to test

GP

Edited by gcpeters on Monday 29th March 09:47

[markh1]

Hi GP,

On your picture below which pin have you counted as number five? Is it five from the right on the pins that the plugs go onto?



Also I can't figure out how to get the boss off so you can get to the left hand side of the pcb.

FarmyardPants said:

Does the steering wheel have to be on the car for the wipers to work (does the wheel make electrical contact with the hub?) Just a thought in case you're trying with it off.

Re the original question, they are all at the front of the car! Could check for an earth somewhere near the horn?

That is a good point, I don't know if the wheel has to be in contact with the boss for the buttons to work. Anyone know?

I will also check the earth by the horn.

Thanks again for the help!

[gcpeters]

its pin 5 from the left

you can see my by pass wire is in pin 1 (thats the whipers)

the wheel doesnt have to be on to work, all tested by myself

with regards to getting to the pcb im a bit confused, do you have a pic? mine just pulled out of the boss (had to pull quite hard)

GP

[rustybkts]

You can test the circuit by shorting between the end pin and the next one to it from either end.
If something starts then that is the supply pin and all is well and either the wipers will start or lights flash or horn go off. I cannot remember which order.

I repaired and improved this poor idea by cutting the damaged end off the ribbon and soldered the ribbon on to the pins of the small PCB in the direction the cable moves.

The ribbon cable has to move at right angles to the PCB pins and soon cracks it where it folds.
I also anchored the ribbon cable with silicon to the hub to remove any stress on the PCB as the PCB was cracked as well.

My Cerb has had three of these ribbons fitted in only 43,000 miles. Hopefully my mod should be the last.

[markh1]

In the picture below I am trying to lever out the boss but it won't budge. I can't see anything on the back to undo, all I have done is taken the central nut out and the mount for the wheel (although I dont think this affects it)

[gcpeters]

ah right now i get you!!

so basically the ribbon cable et all is under there!

what you need to do is re attach the wheel with the allen key bolts and line the wheels up to point straight, then you literally have to pull it straight and hard (yes yes, snigger) and it will come of

if you prise it a bit with a screwdriver at the top this also helps. It sits on a splin (can only go one way) and then the big that bolt (that you have removed) is all that holds it on

GP

[markh1]

thanks for replying so quick! I am constantly going from the study to the garage! I need tinternet in garage me thinks!!

I will line the wheels up and give it ago!

[markh1]

Got the steering wheel off!!

Tried bypassing the pcb with a wire like in your picture but nothing works so I am going to try the earth point where the horns go to which I think is right at the front of the car somewhere!

[markh1]

Earth points all look fine.

This is really starting to bug me now! Mechanical problems are easy to solve! Electrical ones are a nightmare!