Cluster F**kry

[Royalratch]

Hi zone pals.

My speedo cluster (and dash lights in general) have VERY dim backlighting.

I’ve swapped the headlight switch unit out for another, which I understand has the voltage regulator for these lights and is adjusted via the headlight knob dimmer as we know. Not sure it’s made a difference but also tried two other clusters and they stay dim.

Also, on one of the clusters none of the gauges or clocks work.

Mad confused. Help?

[Royalratch]

I know it’s all about Facebook now but...

[Brianmoooore]

Take out the rear ashtray, and then the lamp assembly that illuminates it. Disconnect the brown/white wire and connect it to a good body earth. This will completely bypass the dimmer control, removing it from the equation.
Measure the voltage between the grey/red wire and the good body earth, which should be near 13 volts with the engine running.
The lamps which illuminate the cluster can develop a black film inside their glass as they age, which greatly reduces their light output.
NONE of the gauges work?

[Royalratch]

BM you star!

They don’t - but I’ve basically been cycling through FOUR clusters I have as I thought it was the just the cluster lights. On this current one, only the fuel and temp work - so I’ll return the original and try your advice out.

[Royalratch]

Take out the rear ashtray, and then the lamp assembly that illuminates it. Disconnect the brown/white wire and connect it to a good body earth. This will completely bypass the dimmer control, removing it from the equation.
Measure the voltage between the grey/red wire and the good body earth, which should be near 13 volts with the engine running.

Ok. Did this and getting low milliamps and the bulb in there doesn’t light up. So clearly a (new) issue there. Would that affect the dash lights? I’ve got a brand new headlamp switch assembly which I’ll try also.

Also, the passenger side door light does not come on when I open EITHER door. It is set to the right switch position and it does light up if switched manually. The drivers side door light does come on when I open EITHER door.

[Brianmoooore]

Interior light problem is likely to be brown and red/green swapped over in the light.
I'd be very surprised if the ashtray lamp lit up after you'd disconnected one of the wires from it!
"Ok. Did this and getting low milliamps" ??? This makes no sense whatsoever. I asked for a voltage reading.

[Royalratch]

Interior light problem is likely to be brown and red/green swapped over in the light.
I'd be very surprised if the ashtray lamp lit up after you'd disconnected one of the wires from it!
"Ok. Did this and getting low milliamps" ??? This makes no sense whatsoever. I asked for a voltage reading.

Lol. Obviously it was checked when connected up. Of course you’re right, what I meant to say was I got very low voltage readings from it.

[Brianmoooore]

What I meant to say was I got very low voltage readings!

Which was?

[Royalratch]

Was under 1V. 0.6ish.

[Brianmoooore]

Are your rear number plate lights working properly?

[Royalratch]

Ok!

Excuse the late reply.

Number plate lights are fine.

Voltage across the terminals of rear ashtray light is actually almost bang on 10V.

The same reading with earth at body terminal rises to 11V.

Ignition is on, headlights on, but engine not running - battery attached to conditioner and on full charge.

[Brianmoooore]

If the number plate lights are working properly, it proves the relevant section of the main lighting switch is OK, since they share that section with the panel lights. Earthing the brown/white at the rear ashtray light bypasses the rotary dimmer in the lighting switch, so we can conclude that this switch is not the problem.
If multiple clusters have been tried, and all are equally dim, all I can suggest is that there's a problem with one of two multi way joints buried inside the wiring looms behind the dash. These joints are those where all the grey/red wires join together, and where all the brown/white wires join together.

[Royalratch]

One of the clusters (the current one) is much brighter than the others - though not as bright as it should be.

[Brianmoooore]

The lamps which illuminate the cluster can develop a black film inside their glass as they age, which greatly reduces their light output.

Also, someone may have fitted 5W lamps, which are much easier to obtain.

[martauto]

Also, someone may have fitted 5W lamps, which are much easier to obtain.

Can these get too hot Brian ?

Mart.

[Brianmoooore]

5W lamps most definitely get too hot, and will damage the orange plastic domes.

[Satan]

12V 3W capless lamps are only pennies each,

Order 20 a few extra bits to get you over the £15 limit apply the discount code and hey presto.

[Brianmoooore]

There's no problem in getting the 3W ones, but not from a 'car' shop. The 5W ones are a common front sidelamp/parking light, so are the ones that 'car' shops stock.

[Satan]

12V 3W capless lamps are only pennies each,

Order 20 a few extra bits to get you over the £15 limit apply the discount code and hey presto.

Oooops this was from Carparts4less.........

[martauto]

Can you replace them with LED`s ?
ie, So the dash looks brighter but without the heat ?

Mart.

[Brianmoooore]

You'd have to fix them so that they feed into the plastic light guides, and the dimmer would no longer work without additional electronics.