Dashboard instruments problem.

[Longbaser]

G'day everyone.
I need help with something that started simply enough! I recently put a new CD player into my Sierra ('85 LWB 1.3 styleside), and then decided to replace the speakers as well, with a set of 2-way splits. All fine and dandy until, since I had half the dashboard apart anyway, I decided to pull out the intstrument cluster and clean out years of dust...

Now the turn indicators on the dash are arse-about (left flashes when right is on and vice-versa), and as soon as the ignition is turned on the petrol and temperature gauge needles both zoom up to the top and stay there. Like all Sierra fuel gauges, mine has never gone over halfway before, so this is a change, but I'd prefer to know when it's nearing empty! Seems to me this must be an earthing problem but I've had the instrument cluster out again about six times now and can't see anything missing or loose.

One thing I did notice was that the spot for the L/H indicator globe on the printed circuit looks as though it is worn or damaged, not sure about this. Can anyone suggest where I should be looking for a missing or loose earth related to the instruments?

Any help will be most welcome. This is embarrassing - it seems to support my wife's belief that I am a DIY disaster!

Cheers - Longbaser.

[nicbeer]

ha ha.

yep sounds like u got a short in there for the gauges to shoot up. or earthing out somehow.

check ya fuses and then any new wires added. also check behind cluster for all globes as u have said., even remove the globes and try again to check for shorting.
nic

[Longbaser]

Thanks for the advice Nic.
I had already tried removing and swapping globes in the instrument cluster, so I guess it's a case of patiently retracing every wire in hope of finding the problem.

I have a nasty feeling that when I eventually find it, it is going to be something so bloody simple I will want to kick myself. After 20 years of owning a Sierra, the fun never stops!

Cheers - Longbaser.

[Longbaser]

Problem solved!

My neighbour ran his multimeter over the printed circuit on the back of the instrument cluster, the cause of the trouble was a break in the circuit for the L/H indicator repeater light in the dash. I must have snagged it on that pesky hazard light switch as I was removing the instrument cluster.

A communications technician, one of the best hands with a soldering iron I have ever met, soldered a bridging wire into the circuit (without melting the plastic sheet it is printed on!) and now everything is working A-OK.

That hazard light switch is always a pain when you're removing the dash instruments, something to be careful of. And do I feel silly? Yes!!

Cheers - Longbaser.