Dash lights issue

[mcbonio]

Hey chaps,
Have an issue with the dash lights, I have to smack the top of the dash to get them on. I've checked the plug connections and the bulb holders themselves. All seems ok.

I'm now thinking there's something up with the internals of the clocks.

Anyone had this issue before?

[Brianmoooore]

Which dash lights? All of them, or just the ones in the cluster?

[mcbonio]

Should of mentioned, just the ones on the cluster. All the HVAC panel and clock come on fine.

Sometimes just the light behind the speedo will come on, and I have to tap the dash to get the tacho light on too. Or visa versa. Or sometimes no lights at all.!

[d1mkaz]

Should of mentioned, just the ones on the cluster. All the HVAC panel and clock come on fine.

Sometimes just the light behind the speedo will come on, and I have to tap the dash to get the tacho light on too. Or visa versa. Or sometimes no lights at all.!

same here, must be common fault

[mcbonio]

There must be a reason and fix for it.!

[Brianmoooore]

Not a common fault at all, but if ONE bulb occasionally works, I suspect you simply have two blown bulbs. The ends of the broken filament occasionally touch, and if this happens when power is being applied, the two ends will stick together magnetically, the bulb will light, and may stay lit until the power is turned off.
Don't forget, replacements must be 3W, not 5W, or things will melt.

[mcbonio]

Ok just taken the bulbs out an did a continuity test, they're toast, got some spare in the garage I think.

Cheers Brian,!

[mcbonio]

12v5w or 12v3w?

Might the 5w melt the plastic orange lens?

[Brianmoooore]

Don't forget, replacements must be 3W, not 5W, or things will melt.

Notice: things WILL melt,

[mcbonio]

Hehe, ok Brian.!

[G-Bear]

Interesting, makes sense about the fillement magnetically holing together.

I have this happen every so often, and was alway quite content with the 'tap dash' technique. But perhaps I should add this to my ever growing and non shrinking 'to do' list..

[mcbonio]

I just ordered new bulbs, i think they were 2.50 for 10.!

I hear ya on the to do list, every time I cross one thing out I put another one on..

Brian's knowledge is brilliant, I'd of never guessed thats why the bulbs were coming back on with a smack. I wonder if he can solve my wandering tachometer issue over on the m30 section.

[Brianmoooore]

I wonder if he can solve my wandering tachometer issue over on the m30 section.

That's the problem with the forums divided into many sub sections. I'm not into things nautical, so I rarely look at that section.
MPG meter doesn't take any inputs from the tacho - it uses fuel rate information derived from the injector pulses, road speed data from the differential, and an input from the throttle switch.
Since both tacho and MPG meter are affected, the fault is probably with something that is common to both, which is the SI board, which contains the electronics for both.
There's no electronics on the tacho/MPG meter itself, but it does plug into the main cluster circuit board in a similar way to the speedo. A known common fault with the speedo is cracking of the solder that fixes the connecting pins to its circuit board, and although I've never heard of a similar fault with the tacho/MPG meter, but it could be worth checking out.

[Rav335uk]

That's the problem with the forums divided into many sub sections. I'm not into things nautical, so I rarely look at that section.
.

Come on Brian, I thought you would atleast pop in that section, most of it is as Old as you.

[mcbonio]

Ok so check tacho solder joints.

I changed the batteries on the SI board only a few weeks ago. Perhaps something else is at fault there? How can I test the SI board?

Also, would faulty HT leads create this problem? (wild shot)

[soul4t]

Ah, very usefull! My Tacho side lights up 50% of the time and tends to come on with acceleration! Makes perfect sense! Thanks Brianmoooore!...and Mcbonio for the thread!

[mcbonio]

I changed the bulbs all good now.!