Speedometre dial light

[Chris A]

Hi everyone, I have to admit that I am scratching my head over this one at the moment.

There is probably a simple answer out there, so here goes:

The light for the dial works fine when the light switch on the dash is pulled out, but when I turn the ignition switch to on, engine running or not, the light goes out  The warning lights for oil pressure & charge work as they should.

The light in the other dial isn't affected at all.

Removing the bulb holder from the dial and earthing it elsewhere solves the problem.

So, a conflict of interests between the various bulbs and earthing I assume.

Thanks for your thoughts.

Oh, I should have left well alone. Had the car 3 years and never driven it at night. I was bored last night so said" I wonder if the dial lights actually work" Now I know! ?

[Bordfunker]

Does your light switch have 3 positions:

• Off
• External lights on but not internal
• External and internal

or something like that, it’s been a few months since my lights have actually worked.

I was tearing my hair out trying to work out why my dial didn’t illuminate until Pete pointed out that there were more than 2 positions for the light switch!

Karl

[Colin Lindsay]

1 hour ago, Chris A said:

Removing the bulb holder from the dial and earthing it elsewhere solves the problem.

 

Before I'd got to that line I was thinking "It's an earth..." Just string a more permanent earth to a good earthing point and it should be ok, so long as it isn't a short somewhere. Just smell for burning every few minutes. I replaced the GT6 dash lights with white LEDs a few years ago, and lost the original earth cable somewhere down behind the dash in amongst all the other cables. I just made a new one and things worked fine.

 

[Pete Lewis]

Has to be a bad earth , the other thing is the votage stabiliser sits on fhe back of the speedo  so that may not be earted either 

And (if its got one) be giving daft gauge readings just to help you 

Pete

[Chris A]

1 hour ago, Pete Lewis said:

Has to be a bad earth , the other thing is the votage stabiliser sits on the back of the speedo  so that may not be earted either 

And (if its got one) be giving daft gauge readings just to help you 

Pete

Great minds think alike, fools never differ. I am thinking along the same lines. I started another thread before this one ( voltage stabiliser) as I am getting what I believe to be high readings on both fuel and temperature gauges. A new VS is on order and when fitted I hope all will be sorted. I had thought of running a new earth from the bulb holder itself but decided to wait. 

I bougt an infa red thermometer and used that to check temperatures on hoses, radiator and housing the readings were not overly high even though temperature gauge was close to the hot zone.

Hopefully your diagnosis is the correct one.

[Pete Lewis]

The bulb holder claws earths to the body of the speedo  the speedo should have black earth with an eyelet to fit under one of the Knurled clamp screws this earths the lamp speedo and the stabiliser its linked to all other gauges , its been left off after some previous work

Pete

[mpbarrett]

I had a similar problem, no light on the speedo and very high temperature and fuel gauge readings. the problem  was that I had forgotten to connect the earth connection to the speedo. Its a ring connection on the clamp that holds the speedo in place. 

I stops the back lights working (only noticed at night) and the voltage regulator does not work properly, it produces about 11V instead of the 10V.

So I ownder if you have a fault with the earthing on the speedo?

Mike

[Chris A]

Pete & Mike, an earthing problem is my suspect number 1 linked to a problem with the voltage stabiliser.

The back light works until the ignition is turned on.

I think I will rig another earth wire from the speedo, a test cable in the instance just to see.

[Chris A]

I fitted a new voltage stabilizer today - see otherlink on VS - no difference to dial light problem so fitted a new earth wire and "let there be light". The dial light works whether the ignition is on or off, just like the other dial.