MFA battery etc, blank MFA Clock

Brown and white wire for the MFA to go to the rocker cover stud along with the earth strap, reading on here recomend another to the coil as poor earth for the clocks is the rocker cover stud.

Cleaned these up and me and Jelly repaired the brown white connection, that was bodged.

Plus anyone know the correct size back up battery should be on these MFA Clocks?

My MFA is totally dead, Blank screen, but have rev counter, dash lights etc working.

any pointers please to my quandry?

cheers

chortle

I'm going to ask the obvious…as it's all I know!haha  Have you checked the fuse?  It's the same one as the radio so if your radio's working then scrap that

Does that fuse serve only those 2 parts MFA screen and radio alone? I have all other stuff working etc working on the clocks other than MFA, it's blank no digits at all.
I do have a radio fitted, but not sure how well it's  been done as no speakers work at the front apart from the high level tweeters.
So need to investigate more.
I will make up a wire from the rocker cover to the coil tomorow and see what happens.

It's my understanding these have a battery bit like a watch, so it may be that that's flat. Need to know size and voltage etc. I will need to strip the clocks out but that's no problem just would rather have everything on hand before I start.
Cheers

Chortle

check fuse 3 matey, it does the interior light and the clock on the mfa,
without it (on mine) the mfa is still lit, but no digits at all (just checked)

Cheers Tony.
My interior light works off the switch not the door ones though.

Another thing to have a look at lol.
Just working though the issues, got a nice list forming at the moment.
Will deffo check fuse 3 what amp is it, in case it's missing.
Do you know where the horn relay is what number etc.
Save me looking it up on the sticky on the FAQ.
You done any more, re the roof?

Never heard of the battery back up before. Where's that come from????

 :dontknow:

I read about it on here whilst doing a search.
So is there a batteery or not lol?
Never had MFA before so not worked on these clocks. I did replace the screen in my old clipper clocks.

I will set about adding another earth and investigate further.

any other info appreciated too, so don't be shy lol.

cheers for the replies so far.

chortle

I've had them out more times than I care to think (the clocks!!!  :mrgreen: ) and I've never seen or heard of a back up battery before - nor when I had issues with my Mk2 when they were relatively new.

Once you've got the earth wire to the rocker cover and coil things should look a bit better. The 'pull the fuse out' trick to re-set the MFA seems to work frequently so I'd check the fuse for that.

I've just checked the fuse for you - mines a 15A

Okay pulled fuse 3 15A it turned the radio off .
I reckon the previous owner tampered with it.
My int light does not work on the the door switches.
Also no power to horns.
Relay 6 was missing so I replaced it checked continuity to the steering column.
Normally you hear them click dead as a do do.
Lol. Checked fuse 16 which I believe is for the horn mine us rated at 20a when normally they are 15.

Took a look at the earth wire Braided one from the rocker cover, followed it back and it does go to the coil.
But the the coil strap only had one bolt in it and that was loose. So I cleaned up the area and tightened it up.
Checked for continuity all good.

MFA display still not working.

The reason why the interior light doesn't work off the door switches is because the light fitting it'self is no good.
So I know that's the reason why.

still no horns either.
Any one got a pin out for the relay so I can use my multimeter in the fuse board slots to test the voltage?

cheers Guy's

follow the red wire from cluster to the fusebox, see if you can spot any bodgery. check at the horns for ign live at the black/yellow wire and check the connections are clean. does the relay click when you press the horn? also check earth from rack to chassis

Thanks all,

Johnny,
The no6 relay was missing so bought a new one.
Made no difference, still no horn and no relay click.
I had the wheel horn pad off and checked the earth wire from the wheel and it is earthed to the column, using the continuity test I then clipped a length of wire to the brown and then tested the it against various points around the engine bay. Had continuity. Didnt check it at the steering rack connection. All I could manage was a cursory look the short brown wire from the rack is connected.

So will check that tomorow.
Either way the relay is not energising.
So I should have live feeds with the ign on at the horns them selves?
Problem is I am trying to cure many probs at the same time.
There is a mass of wiring under the fuse box so it needs sorting properly.
There are wires spliced in at the door pins on closer inspection these trigger the alarm.
Also a White  (or grey) yellow stripe is left un plugged I think that is for fog light, not checked it works though.

I have normal dash lights when the headlights are switched on and they dim using the thumb wheel.





Which red wire johnny?

Cheers

from the cluster to the fusebox, thats the power feed for the dash clock

the horns should have ign live at all timnes, its the earth that is switched by the relay. if the relay isnt clicking when you push the button its probably the column earth that is bad, or the wiring or stalk. take the wheel off and check the condition of the wheel contact, might have been snapped off or bent out of shape. you can rule out the wheel by bridging a wire from the column to the wheel contact pad on the stalk, this should fire the horn or at least make the relay click.

Cheers Johnny.

I shorted the copper tab that runs on the horn ring under the wheel to the column prior and no relay Click. I have tested for continuity from the horn push wires and they are earthed, I checked by connecting to various parts in the engine bay so I know at the moment the earth path appears to be ok.

So if I Short the blk/yl wire on the horn to ground with ign on then it should sound?

That would rule out the horns themselves being faulty.

I have noticed the MFA stalk switch does not slide across and stay between positions 1 & 2. I presume it should stay where I slide it to either to No1 or 2?
It could be the stalk is FUBU.

At least I know I only need a new interior light.
Thats one off my list lol.

no run the black/brown wire at the horn to ground with ign on to make the horns work, if you short the black/yellow to ground you'll blow the fuse

check fuse #18, thats the power input for the horn relay, the horns themselves are on fuse #16.  if you want to check the horn relay socket pin 4 should be ign live, pin 1 should be earthed when the button is pressed, pin 2 should be an earth and pin 3 is the horn earth black/brown wire.

the stalk should click to 1/2 just off centre, you slide and hold it all the way across to reset the memory for the mfa counters in 1 or 2 depending which way you slide it if that makes sense

MFA not touched that yet.
My switch does appear to work mechanically, so thanks for that.

Inso far as the horns.

Now checked continuity from the Brown wire from the horn push all the way to the Steering rack all okay there.

With these horns they are wired seperately running back to the fuse box looking at it.

On my old car they were wired into a multiplug, so easy to test.

I disconnected the horns completely and wired them to the battery to test them and one sounds the other is a duff one.

I took the wheel off and inspected the stalks and continuity tested them from the horn tab to the pin No 3 by the looks of it, this connects to Brn/Bl I think and all okay there.

So I shorted the socket for that pin 3  to ground to see if anything happened still nothing.

So really need to trace that back to the fuse box and check for continuity.

I looked at fuse 18 and 16. Number 18 had a 30 amp fuse in it ????? So replaced that with a 15A as per the handbook.

Swapped the new relay for a secondhand one and still nothing. No clicking dead as a do do.

I couldn't really get to the wiring at the horns due to the way are enclosed in the connectors.

Do you have a drawing showing the pin configuration of the realy  as you look at it please, it's tricky looking upside down lol.

In reality then the horns are postive fed all the time with IGN on, so If I set the multimeter to volts and connect the Positive to the BLK/YLW and the negative to the earth on the chasis I should get a 12v reading, that would show supply?

If connect negative to the BRN/BLK it would give nothing unless the horn was pressed and the Relay activated?

I have a sinking feeling it's the fuse box.

Would a faulty Ignition switch cause this?

Looking at the heated seat plugs under the seat that are disconnected for some reason?

These are also on fuse 18 acording to the handbook.

Inspecting the drivers seat multiplug shows brown marking on the white plastic symbolic of over heating.

The seats apparently don't work, however I have not reconnected them to try, if they do.

Would having the seats disconnected affect the Horn also?

Somethings are wierd that way.

Cheers so far

chortle

fuse 18 is just for an ign live feed. looks like the seats malfunctioned and some genius thought that rather than trying to fix the problem, he would bodge in a bigger fuse.

also the wiring to the horns sounds dodgy, both should join together at a 2 pin plug near the batter, which then runs back to the fusebox.

if you look at the fusebox sticky it shows relay locations and socket pin numbers

The wiring on the horns is factory standard, it runs in the loom properly and the connectors are OEM. They have the metal clip wire that that secures the 2 parts of the connector together, bit like the connectors that go to the centre lights on the grille. If that makes sense.
 
On my old one they just were wired in parralel and then to one plug and one set of wires back to the fusebox.

I think VW did this mod on later cars due to the fact that twin horns fail as the current drain through the single wires seperating to the 2 pin multiplug can cause the horns to stop working, really common problem.

According to the Handbook Fuse 18 serves Horn (switch current) Coolant warning lamp, Brake warning lamp, seat heating. I pressume brake warning lamp is the one that illuminates when you pull the handbrake on? This is illuminated all the time on mine too, I think it has a faulty hand brake switch too.

I see on the piccy on fuse box Socket L is for the horns and can see the wire I need on there, so testing its continuity to the plug at least should be straight forward now.

Any more ideas?

ah ok, just misunderstood what you meant is all. as i say 18 is an ign live feed for various things, one of them happens to be the horn relay if one is fitted! if vw listed EVERYTHING each fuse did then the handbook/fusebox cover would need to be pretty huge

test the fusebox socket for the horn relay as per my post on the last page, and check out the socket on the back too. hopefully that'll tell you why the relay isnt clicking!

plus the GRY/YLW on the socket to the right of Grey one is this the rear fog light? As mine does not work and I seem to have a corresponding plug empty hanging around under there.

Cheers