Gauge cluster problems

[rabbit gti guy]

Ok the other day i was installing my stereo...and i dont really know what i did but i was hooked into a wire that i thought was my old deck power/ground source...but when i turned my lights on the deck lost power...and vice versa.   well anyways i hooked in power somewhere else.

that being said i started my car and my gauge cluster doesnt work anymore.   It lights up, the clock on it works, and the speedo obviously, but the fuel gauge/water temp/and none of the battery/glow/signal lights on the cluster work.

is it possible that i blew the cluster?  cause i took it apart and none of the bulbs are blown.   maybe a relay or a fuse somewhere?   For a while sometimes the lights on the cluster flicker (glow/oil lights) when im driving for no reason, and now they dont work at all.

any one?

thanks

[rubadubdub]

These things are a pain to sort out and i cant tell you for sure whats wrong but i can give you my experiences from a couple of dodgy dash boards.

Firstly check ALL your fuses.

Secondly, following Occams rule (start with the most obvious before doing anything complicated), take a look at the coloured wires you cut previously. Ensure they're back as they were originally and find them on a wiring diagram in haynes or bentley to see what they feed in case it sheds any light. If they've been reattached check the connections are ok and any bare edges are not touching any bare metal or other wires.

While the dashboard is out check the grounds and 12v feeds with a multimeter to see whether things are coming on as they should.

Finally if you removed any switches when you took the radio out, especially the hazard switch, check its wired up properly again. I had all the dash lights go out apart from the indicator because the hazard switch on my mk1 golf was broken.

Cant say specifically whats wrong in your case but all the things that are broken share a common power source and ground (i believe). Theres a voltage stabiliser that changes the power from 12v to 10v on the dashboard and that may have blown (try search function).

If you have a spare set of clocks which you know work fine then by swapping them you can narrow it down to either wiring problem or clocks, assuming fuses are fine.

[rabbit gti guy]

Ok.....so heres the update.   I had the wiring out of my rabbit and patched up a few sketchy parts...mostly being the wiring for the charging system.   I soldered all the joints best i could.   The wiring is according to the manual now.   Basically i have a brand new battery, and my alternator is only a week old.   What happens is when i first start it up with the battery fully charged it starts fine, but the alternator isnt doing its job.    At idle just after starting, if i take the ground off the battery the car stalls.   Also i had a multimeter on the battery and the voltage reads 12.6 volts...with the car running or not.   oh and the dash warning lights and temp/fuel gauge dont work at all, except for the high beam indicator light.

But if i rev the motor...and i mean i have to basically jump it to redline, the alternator seems to kick in, for some odd reason.  the fuel gauge reads, the signal light indicator works, etc...i read 13.8 volts at the battery and if i do the simple remove the ground cable, the car doesnt stall.   and after this it works fine untill i shut it off.   But after shut off and restart i have to rev it again to make the alternator kick in.   Im not really sure what to do...i think it might be the alternator but ya its brand new and it works after u rev it.

so any ideas?

[MikkiJayne]

Don't take the ground off while you're running!  :shock:  You'll likely destroy the alternator voltage regulator like that, if you haven't already!

The alternator must be connected to the battery for it to be able to regulate it's output. If not it will go nuts - it's not self-sustaining like a dynamo is - it needs a load to stabilise it.

The cluster provides a 12V supply to the alternator on the blue wire. Terminal 'D' I think. This is what makes the charging light in the cluster work. Are you getting that light on when the alternator isn't charging? If not then thats likely to be the problem. It could be that the voltage on that terminal is very low, hence why it needs to be spinning very fast to start up.

Put a meter on the D terminal and see what you get in the following conditions:
Ign on, engine stopped, D disconnected - 12V (light off)
Ign on, engine stopped, D connected - 0V (light on)
Engine running, alternator not charging, D connected - 0V (light on)
Engine running, alternator charging, D connected - 14V (ish) (light off)

Hth, Mikki x

[rabbit gti guy]

ok so im not sure what u mean by "D"....but theres a blue wire in my gauge cluster clip that i pulled out and tested.

1 - .3v - no light
2 - 0v - no light
3 - 0v - no light
4 - 13.92 V no light (as i was reving the motor the volts were jumping up untill it peaked and started reading 13.92

so basically each time the light doesnt work.   what do i have to do?  im lost

[MikkiJayne]

D is the terminal on the alternator that has the small blue wire on it. On early V-belt alternators it will be a ring terminal on a stud, and on later serp-belt ones it will be one pin of the two-pin connector (the other is W).

You need to do the test at the alternator as it's the cluster that provides power to it. If you disconnected the cluster then the tests I suggested won't give the expected (or any) results.

Does the light come on when you switch on the ignition before you start the motor? If not then thats a definite problem somewhere - we just need to work out where  :wink:

Mikki x

[rabbit gti guy]

ya the light doesnt come on at all...but i think it is a bad connection on my gauge cluster.  my alternator has a 3 wire plug on it...2 for the power and the one blue wire that your talking about

[rabbit gti guy]

ok so i think i understand a few things now.   on the alternator theres a three wire plug...2 red wires and a blue wire.   when i did the test that you told me, i measured 0V, there was no light on ever, and when it was running i only got .3V.   If i check the blue wire at the gauge cluster it reads the same.   well I understand that the 2 red wires are constant power, and the blue wire is supposed to have 12V as soon as u turn the ignition on to signal the alternator to start working.   when its running its supposed to jump to about 14V.   Correct?

well basically theres nothing wrong with my alternator, because i ran a temp blue wire directly to the battery and it jumped to 14V right away when i started it up.  

the manual doesnt help me much....but i need to know where the blue wire goes....when it comes off the alternator.   does it go through a relay?   where does it find it self on the fuse panel?   what could be wrong?

thanks

[rabbit gti guy]

well ive been screwing around with it a bit...and theres some stuff i cant figure out.   the plug that goes into the cluster...well if i dont plug it in all the way and fiddle around with it a bit, the fuel gauge works, glow plug light and battery light work as well.   The ebrake light is bright, as it should be.   BUT, the headlight switch has to be ON for this to work and the cluster lighting has to not work (after i play with the wires the lights go out, and the fuel gauge/glow plug light/alternator light work.)  as soon as i plug in the clip all the way, the cluster lights come back on and all the gauges/lights that worked before cease to work.

Also to do with the alternator and the blue wire talked about in the previous post, if i have the cluster plug unclipped partially as said in the previous paragraph, and the alternator light working, if i start the car and tap the throttle the light goes out....  

wiring is so frustrating.   a whole week and endless hours outside in the cold (i dont have a shop or garage i can work in) and im not really any further ahead than i was.   im not sure what to look for and its starting to get really annoying....grrr

but ya any help is very much appreciated.  thanks.

[rubadubdub]

if i have the cluster plug unclipped partially as said in the previous paragraph, and the alternator light working, if i start the car and tap the throttle the light goes out.

Assuming the light was on only when you turned the key to the first click then it went out after the engine started and throttle blipped then thats whats supposed to happen so at least it means it can work and the bulbs not blown.

The fact that fiddling around with the connector can get it to work suggests that its to blame. I'd pull it out and have a good check of each of the pins and make theyre all ok. Then check the piece of plastic circuit board where they contact the pins as that can get damaged.

Carefully check the whole circuit board for any damage as the 'light switch turning on/off affecting dahboard components' thing happened to me when the board was ripped.

Finally check the grounds. I dont know what year your car is but the grounds tend to all converge in a ring somewhere behind the dash board. Its on the left hand side on my 83 golf (gas) but dont know where it is on the mk2. Grounds are also a very likely candidate when stuff is not turning on as it should do.

[rabbit gti guy]

its an 84 Rabbit TD.   anyone have a detailed list of what wires are what according to the numbers on the cluster plug?

[rubadubdub]

From haynes: 1978-1984 mk1 golf diesel (this is a UK book so maybe different):
14 point instrument multiplug (wire colour)

1. instrument lighting (?)
2. earth (brown)
3. fuel guage sender (? 'VI' is german abbreviation of the colour/black)
4. coolant temp sender (yellow/red)
5. vacant
6. clock (red)
7. main beam warning light (blue/white)
8. vacant
9. oil pressure warning light  (blue/black)
10. glow plug warning light (blue/green)
11. vacant
12. alternator warning light (blue)
13. turn signal warning light (blue/red)
14. live (+) wire (black)