Faulty temp gauge?

Sorry if this has already been answered but I have had a good search and not found a cure.
My temp gauge always shows zero. The red light flashes when i turn the ignition on but the needle doesn't respond at all.
I did the ground test to check the sender and the needle slowly climbed to just under half way.
I'm guessing it could be either the wiring or the gauge?
Also the digital clock doesn't work It's an every day car so without seeking advice first I didn't want to open up the dash and start poking around. Any help would be great!

sounds like the clocks or wiring to them at fault, if you earth it the gauge should go to full. check the eaths on the head if it has an mfa there should be a brown/white somewhere. check the clock fuse as well

Earths is a good place to start as rubjohnny said - i had a lot of unpredictable happens on my car and it all centered around having a good earth.

Once you have ensured a good earth it is then up to identifying the faulty item - I'm guessing the sender is the cheapest thing to try first.

Definently sounds like gauge or wiring. If you have a multimeter, you could take the clocks out and test by applying a 12v feed (not directly to the gauge, because it goes through a regulator), earth, and earth the sensor input for the gauge. Should go all the way across. 

Not sure about the clock. I think it just needs a regulated feed and an earth. May be a 12v feed though. (Not very helpful!)
Just trace the wires on the circuit board on the instrument panel. 

I think it is safe to assume that your sender is not at fault, however, you can test it by putting it in a pot of water on the hob, measuring the temperature, and testing the resistance. It should be about 150 ohms at about 90*, around 270 ohms when the water is at room temperature.

I found a useful page in my Haynes, I'll post it if you want. It pretty much just covers what has been discussed though.

My car had the same symptoms when I bought regarding the needle and the light.  I didn't bother testing anything as the sender looked in a sorry state so I changed it, and the gauge starting working fine.

If you are convinced it is not the sender, I would try changing the voltage regulator on the back of the clocks.  Could explain why your clock doesn't work either.

Thanks for the great advice. Sorry for the slack reply. Had my first car show this weekend so I've been busy making it look pretty I cleaned up all the earths I could find in the engine bay as they were all filthy from a bad oil leak it had before I owned it. I don't know if it's related or I've done something else that might have affeccted it, but now the gauge goes up 2/3 or the way when grounded. Still slowly though. I followed the earth from the temp sender and it goes through the firewall. Is this the earth I should be checking? Is there an easy way to access this without taking it all apart?

I had a look at the fusebox and there was a slight difference to the labelled diagram I was looking at.

This is the diagram I've been looking at:   http://ww2.justanswer.com/uploads/EU/eurotec/2013-01-11_215925_90-93fusepanel.png

And this is my fuse box


As you can see slot 5 is missing a 15amp and 12 has a 15amp where the diagram says open. I don't think I'm having problems with the fuel pump or heated oxygen sensor but then again I don't really know what they are . I didn't to swap them over incase it was damage something. The more I think about that now the more stupid it sounds lol. Electrics really aren't my forte. But perhaps this could be related to the lcd clock? The clock is labelled as 3 but the interior light, radio and cig. lighter all work perfectly.

Could someone send me a link for a decent temp sender? Are the ebay ones any good? If I haven't mentioned already it's a 1.8 1991 cabriolet.
I'll try and get the clocks out next weekend if I get the time. Thanks again for the advice. Can't wait to sort this out. It's unearving not knowing the temperature of the engine!

Here's my car with my old man's Triumph. Shiny

http://bit.ly/16LD2MB
This what I need?

if its a carby then no fuel pump fuse as its mechanical

yeah that one in the link is correct for the later cars with 2 pin coolant temp sender

New sender in and it's showing signs of life but I don't think it's reading correctly. No where near hit enough in relation to the engine.
I'm having difficulties getting the clocked out. I've got all the switches and screws ff and its so almost free but its stuck somewhere above the casing for the radio. Probably something really simply but I've tried everything I can without forcing it past breaking point. 
Can you tell me where the earth from the sender goes to?

Thanks a lot

do you mean the trim? there are 2 screws in the top above the clocks i think, pluys another behind the radio so that needs to come out first.

sender earth taps into the engien loom somewhere, if you suspect it then splice another earth into it to the head or battery -ve

My gauge reads high 
Never overheats as fan cuts in. 
But if i apply an 80ohm resistance to substitute the sendor it reads midway - 150ohm it reads low.
So are there different clocks?
Mine an 85 cc with the single temp gauge top middle. 

clocks & sensors all the same spec, you either have a sensor or gauge which is slightly out or the thermostat is a little lazy or the engine really is running slightly hot.

for the thermostat check stat housing rad hose, it should stay stone cold till gauge gets to about 1/2 then warm up. if the gauge is always a little high it may be the rad is too small or clogged up inside.

if coolant system is all ok then as long as you know what the 'normal' is for your car you're ok.