B4 TDI Rev Counter

Subsea7 · 07-09-13, 07:08 PM

Its not working, not a flicker - got the schematics for the 1Z B4 but its only shows fuse F12 supplying the power, also to the reversing light switch...which works - well the lights do, so not that, but the owner before me had fitted reversing sensors which I disconnected due to the obvious connection but still no joy. CHecked all the fuses in the scuttle panel box, all ok 0 are there any other fuses anywhere?

Any ideas? Anyone know where the speed sensor is, and how you get the instruments out? Cant see no screws....

Cheers for any help you can give.

Weirdly, also the rear demister seems dead, and the fag lighter is only getting warm, like its getting reduced voltage or a bad earth, but everything else works. Oh and no glowplug light but starts like a peach.

msh · 07-09-13, 09:48 PM

You're digging from the wrong end. If the rev counter does not work, then most likely there is bad contacts or broken traces in instrument cluster. If that would be caused by any fuse, whole cluster would be dead. Don't worry about any engine speed sensor either - rev counter is supplied with signal by ECU, so if the speed sensor would be defective, the engine wouldn't run.

To remove instrument cluster, you have to remove upper trim of light switches by unbolting both screws from behind and then there will be two bolts keeping the cluster in place. Turn it with PCB down, unplug connectors by pulling clamp on each with flat screwdriver, afterwards, remove cluster. Steering wheel could be left in place.

How does looks like "demister seems dead" - does the light in switch iluminate and the rear window just doesn't heats or what?

Cigarette lighter itself is probably dead, check it. Bad connection for cigarette lighter socket is very very unlikely. Of course, you can check if the fuse has bad contacts because of oxidation.

As for glowplug light, TDI uses them IIRC below +5c, so it shouldn't use them now.

Subsea7 · 07-09-13, 10:04 PM

Na mate the cig lighter gets warm if held in for a while, and the demister has no light or action, windows stays misted up.

Also noticed the stereo and the interior light if on, will often cut out and the stereo needs settings replaced, so the main feed is intermittent.

The 1Z has a fuse, S12 that only feeds the rev counter and the reverse lights, I have the manual for it.

msh · 07-09-13, 10:34 PM

If that's what exactly that manual says, don't use it anymore

I have schematic - not only that fuse powers whole instrument cluster, apart from illumination, of course, but also a bunch of other stuff, although it's quite likely your B4 has almost nothing of that stuff.

Demister is powered by fuse number 16. If it's fine, you can look for another switch. In that case I would recommend you to fit one from pre-facelift B5 A4 or C4 A6 - it has relay inside - only it requires connector swap as well.

If not only you're experiencing problems with cigarette lighter but also stereo and interior light, then check fuse number 4, does it have oxidation on it etc. All those three things are powered by that fuse - clock as well.

Subsea7 · 07-09-13, 10:45 PM

clock works, the only concern is the rev counter cos I hate not knowing what rpm im going to. Demister of course for winter. Cheers for the tips. do you have a PDF of the manual you have? I think my manual is too new, but says 1z audi 80 TDI and is a audi publication, so its wrong?

The car is a Sport TDI, 4 spoke leather wheel, steel tilt and slide sunroof, abs, electric mirrors etc and a 3 pin injection pump plug.

Any help in identification?

msh · 07-09-13, 11:07 PM

I have no manual, apart from B3 haynes manual and B3 bentley manual. As for schematics, I use mitchell on demand schematics from this site http://autolib.diakom.ru/CARS2/ . Fortunately, there is almost no difference between B3 and B4 electric equipment, apart from some things

Subsea7 · 07-09-13, 11:12 PM

heres the B4 manual I have:

http://s2central.net/80TDi/Schematic...4/C-46-all.pdf

See the S12 fuse on page 7, 46/6 shows S12 only supplies the rev counter G5 and the reverse switch:

That page in Russian, cant read that mate,

BTW mine is an early 1z, no oem immobiliser at all, and no chip in the key. big plastic AFM. Diagnostic connectors are in the engine bay fusebox, 2 x single k-line connectors. Very early OBD implementation.

msh · 07-09-13, 11:17 PM

No offense, but you need either glasses or use magnifying function for your PDF viewer, as it is visible that T26a/16 pin supplies power to other things as well, not only rev counter - only that dot isn't very round one

msh · 07-09-13, 11:19 PM

You don't have to read the russian texts - just click on Принципиальные схемы in audi subcategory, third from top.

msh · 07-09-13, 11:22 PM

And, those mitchell on demand schematics are american schematics, which means that 1993 Audi 90 is the same as european 1992 Audi 80 and also no TDI schematics, only 2.8 for B4 and 2.0 8v and 2.3 10v for B3, but in any case rest of the stuff remains the same

I'm using only these schematics and so far I've only found once or twice different wire color than in those schematics.

07-09-13, 11:12 PM	#7
Subsea7 Grown up member Join Date: Sep 2013 Location: Fife Posts: 21	heres the B4 manual I have: http://s2central.net/80TDi/Schematic...4/C-46-all.pdf See the S12 fuse on page 7, 46/6 shows S12 only supplies the rev counter G5 and the reverse switch: That page in Russian, cant read that mate, BTW mine is an early 1z, no oem immobiliser at all, and no chip in the key. big plastic AFM. Diagnostic connectors are in the engine bay fusebox, 2 x single k-line connectors. Very early OBD implementation. Last edited by Subsea7; 07-09-13 at 11:22 PM.

07-09-13, 09:48 PM	#2
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	You're digging from the wrong end. If the rev counter does not work, then most likely there is bad contacts or broken traces in instrument cluster. If that would be caused by any fuse, whole cluster would be dead. Don't worry about any engine speed sensor either - rev counter is supplied with signal by ECU, so if the speed sensor would be defective, the engine wouldn't run. To remove instrument cluster, you have to remove upper trim of light switches by unbolting both screws from behind and then there will be two bolts keeping the cluster in place. Turn it with PCB down, unplug connectors by pulling clamp on each with flat screwdriver, afterwards, remove cluster. Steering wheel could be left in place. How does looks like "demister seems dead" - does the light in switch iluminate and the rear window just doesn't heats or what? Cigarette lighter itself is probably dead, check it. Bad connection for cigarette lighter socket is very very unlikely. Of course, you can check if the fuse has bad contacts because of oxidation. As for glowplug light, TDI uses them IIRC below +5c, so it shouldn't use them now.

07-09-13, 10:04 PM	#3
Subsea7 Grown up member Join Date: Sep 2013 Location: Fife Posts: 21	Na mate the cig lighter gets warm if held in for a while, and the demister has no light or action, windows stays misted up. Also noticed the stereo and the interior light if on, will often cut out and the stereo needs settings replaced, so the main feed is intermittent. The 1Z has a fuse, S12 that only feeds the rev counter and the reverse lights, I have the manual for it.

07-09-13, 10:34 PM	#4
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	If that's what exactly that manual says, don't use it anymore I have schematic - not only that fuse powers whole instrument cluster, apart from illumination, of course, but also a bunch of other stuff, although it's quite likely your B4 has almost nothing of that stuff. Demister is powered by fuse number 16. If it's fine, you can look for another switch. In that case I would recommend you to fit one from pre-facelift B5 A4 or C4 A6 - it has relay inside - only it requires connector swap as well. If not only you're experiencing problems with cigarette lighter but also stereo and interior light, then check fuse number 4, does it have oxidation on it etc. All those three things are powered by that fuse - clock as well.

07-09-13, 10:45 PM	#5
Subsea7 Grown up member Join Date: Sep 2013 Location: Fife Posts: 21	clock works, the only concern is the rev counter cos I hate not knowing what rpm im going to. Demister of course for winter. Cheers for the tips. do you have a PDF of the manual you have? I think my manual is too new, but says 1z audi 80 TDI and is a audi publication, so its wrong? The car is a Sport TDI, 4 spoke leather wheel, steel tilt and slide sunroof, abs, electric mirrors etc and a 3 pin injection pump plug. Any help in identification?

07-09-13, 11:07 PM	#6
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	I have no manual, apart from B3 haynes manual and B3 bentley manual. As for schematics, I use mitchell on demand schematics from this site http://autolib.diakom.ru/CARS2/ . Fortunately, there is almost no difference between B3 and B4 electric equipment, apart from some things

07-09-13, 11:17 PM	#8
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	No offense, but you need either glasses or use magnifying function for your PDF viewer, as it is visible that T26a/16 pin supplies power to other things as well, not only rev counter - only that dot isn't very round one

07-09-13, 11:19 PM	#9
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	You don't have to read the russian texts - just click on Принципиальные схемы in audi subcategory, third from top.

07-09-13, 11:22 PM	#10
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	And, those mitchell on demand schematics are american schematics, which means that 1993 Audi 90 is the same as european 1992 Audi 80 and also no TDI schematics, only 2.8 for B4 and 2.0 8v and 2.3 10v for B3, but in any case rest of the stuff remains the same I'm using only these schematics and so far I've only found once or twice different wire color than in those schematics.