Dial circuit wiring...

[kayzee]

Hi guys I have posted these pictures previously but I need to get this sorted so here's a bump, hope you don't mind. Basically I have no lighting behind the speedo or rev counter... it's not the dimmer, and I've had that apart and everything seems okay (even though it's held on with tape!)



I got the dial section out and checked the bulbs... seem fine. Fuses seem okay too. Asked advice up my garage and they said it might be a weak connection in the actual circuitry. They have experienced it before on other cars. I'm going to take it to work as we have some right electronics boffs there, hopefully they can help me out. But I was wondering if you knew of any common similar problems with the dial section. Here's the pics I took last time it was apart, thanks...

[bigdavec1974]

hey mate. electrics aint my thing im afraid but in theory i think the dimmer alters the volts the dash lights will recieve, correct? If the dimmer is removed and the circuit incomplete then no lights. So then if ya dimmer switch if fubar then no lights. Would bypassing the dimmer , ie joining the 2 wires, thus creating the circuit make the lights work, or errrr would stuff blow up. Someones elses help is needed, its all just theory

[IANMM]

yep just join them to take the dimmer out the loop

[Brigsy]

Check for breaks in the printed circuit board on the clocks, if its all present & correct look at the connection from bulb-circuit.

I personally plug the clocks in, turn the lights on & twist/swap the bulbs until they work.

[Ian S]

A volt meter / multi meter will tell you in as little as a few seconds where the break / corrosion / loose join is / are.

There is voltage and current there on the instrument panel for the other bulbs.

So if just two are not working that narrows it down a lot.

[bigdavec1974]

on another note, just drive to romford and ill swap my clocks and dimmer over and see where ya problem is. in the day time ofc At least give you somewhere to start

[kayzee]

A volt meter / multi meter will tell you in as little as a few seconds where the break / corrosion / loose join is / are.

Brilliant. I have one at work so I'll get on this on Monday.

hey mate. electrics aint my thing im afraid but in theory i think the dimmer alters the volts the dash lights will recieve, correct? If the dimmer is removed and the circuit incomplete then no lights. So then if ya dimmer switch if fubar then no lights. Would bypassing the dimmer , ie joining the 2 wires, thus creating the circuit make the lights work, or errrr would stuff blow up. Someones elses help is needed, its all just theory

Yeah that sounds good mate... definitely will look into that after the multimeter test.

on another note, just drive to romford and ill swap my clocks and dimmer over and see where ya problem is. in the day time ofc At least give you somewhere to start

That's another option I'll let you know...

[kayzee]

Just one more question... the blocks over the actual dials, is it worth taking them apart as well? I didn't so far as it looks a bit fiddly and I'm sure to break something what's inside lol...

[Nick k]

Are the heater controls lighting up?? They are on the same circuit as the dials and would point to you in the right direction if they are not working either??

[kayzee]

Umm... I've not actual used the heater yet so not sure

All the little icons on the on the dash are lighting up though!

[Sparkie]

id say that the actual bulbs are blown...

[kayzee]

Unfortunately not multimetered every connection and bulb today and everything's fine... am in the process of cleaning up the connections anyway, maybe I disturbed something so I'll chuck it back in tonight for one last go. However I think I'm gonna have to go with bigdavec1974's suggestion of trying to bypass the dimmer. What's the procedure for this? Is it just a case of connecting the two blue wires together? What does the orange one do...

I don't wanna go boom

[kayzee]

Are the heater controls lighting up?? They are on the same circuit as the dials and would point to you in the right direction if they are not working either??

No I don't think so after checking, what is actually meant to light up? It's like nothing's being activated after I turn my lights on!? I was thinking about ordering another dimmer just to try it, they're only a few quid.

Worth a go you think?

[DaveMayGTT]

Its best with these things to look calmly at 1 thing at a time. If none of the other lights on the same cricuit are working then it point to a fuse problem. So look down that path Theres no point ordering another dimmer when you can just join the 2 wires going to the dimmer together to find out if its the dimmer or not. If it is the dimmer when you join together the 2 wires the lights on dash will come on full brightness but when plugged into the dimmer nothing will work. Alternatively if you dont want to touch the wires do a resistance check across the 2 connectors on the dimmer with your multi meter.

[kayzee]

You mean between the two metal prongs sticking out? Sorry I'm not too hot on electronics really...

I can see if I can borrow a multimeter from work is there any other tests worth doing whilst I'm at it?

[DaveMayGTT]

If your going to do the resistance test rather than join the wire then you test between the 2 metal prongs. Have the dimmer set to all the way up which will be basically no resistance. Have all lights off so no current is there, set it so when you touch the 2 probes together you get a nice beep basically to show dead short and then put the probes on the 2 metal bits on back of dimmer. You should get a beep with dimmer set on highest brightness and as you roll the dimmer you should see the resistance value change on the read out. If you see nothing at all when going from probes not touching anything to them being on then its shot.

[kayzee]

Damn... it works lol.

So... bulbs = fine, circuitry = fine, fuses = fine, dimmer = fine.

Has to be the wiring doesn't it!? Can't think of anything else. I suppose there's no point in connecting up the wires to bypass the dimmer as we now know the dimmer is okay. Is there a way I can test the blue wires as in my first picture? Guys at work told me to be careful about blowing things when attaching things to those wires!

Help! At the moment I drive my R5 in the day and my Punto at night

[bigdavec1974]

To be honest mate, meet me on Saturday morning and we can pop down and see rick. He prolly tell you in a few mins what's wrong.

[kayzee]

Hi mate sorry I never replied, had other issues to deal with

Anyway general update...

Still not go anywhere with this. The wiring from the dimmer to the instrument panel is working okay as the resistance changes when I move the dimmer up and down. Someone suggested it could be a bad earth, but seeing as though all the lights on the panel work from the same earth, I can't see that being the issue. My bulbs are all definitely fine as I have a test machine at work which we hooked it up to and it lit up beautifully with 12-13v going through it! I have four people working with me that all have being in the electronics field for over ten years but they're rapidly running out of ideas tonight's test is to check the ohms going through the bulb connectors with a bulb out to see if there's power running to it without the key turned a notch. I have tried bypassing the dimmer, but unfortunately no luck there.

In my opinion it has to be something do with the wiring from wherever the connector block (for the panel) goes to...

But then again I'm still getting power so, I dunno! Also, I haven't got any kind of lighting on my heater controls, could this be causing the problem? I guess they're on the same connection.

[Ian S]

So, you've established at work that the instrument panel is fine. All the lights work when powered up.

So, that means there no power reaching the instrument panel.

What you need to do is obvious and simple.

Just use the multimeter on Voltage setting and connect the black wire to a chassis earth to begin with (then later if you found the supply is OK, to an instrument panel earth to rule out instrument panel earth as the problem) and the red wire to the power supply connector.

I've forgotten now, do the keys needs to be turned first in the 5GTT? And the lights switched on.

If there's +12V there, the connector is at fault.

If not, work you way back until you find the break.

Or work your way forward from a known working point.

If you know which fuse is the one feeding the instrument panel put the probes into one side of the fuse socket, then the other. One of those should have +12V.

Next thing would be the switch? Or a relay module perhaps?

[kayzee]

Thanks Ian, I have done what you said. At first I forgot to do the tests with the lights turned on, so I'll post both set of results. Also, because I've had my power on so long (doing other things to) my batteries almost dead so whether these readings will actually help or not!?

Lights off:

Pin 9 on connector (output): 0v
Pin 2 on connector (input): 3.6v
Dimmer input: 5.9v
Dimmer output: 0v

Lights on:

Pin 9 on connector (output): 2.5v
Pin 2 on connector (input): 125v
Dimmer input: 300v
Dimmer output: 2.7v

Pretty varied results there! From the wiring diagram it shows the connector block going to item 440 which is 'wire joint no.7" do you know what this actually is? I don't really know where to chase back more. Oh and also in the Haynes manual, no fuse seems to refer to anything to do with the instrument panel

I'm still thinking it could be something to do with the heater lights not coming on as well, maybe a short circuit... think it's worth looking into?