fluctuating volt and temp gauge

[clutch]

hi guys, my volt meter fluctuates wildly between 12 and off the gauge randomly while driving, it isn't in relation to revs or speed (but usually only happens when driving, not stopped), it just does it randomly, and if i have my lights on, they will go brighter when spiking just like im flashing my high beams. now i understand that this could be the regulator in the alternator? but what i dont understand is why my temp gauge is relative to the volt gauge, when my volts spikes up to 16, my temp will spike to the red bar, and when the volts come down to 12 (or 14 when driving) it will come back to normal operating temp (in the middle somewhere).

my questions are, to begin with, does this sound like the regulator is making my gauge spike up and back down randomly? and secondly, why is my temp gauge relative to the spikes of the volt gauge?

id like to add that this is a vc sle cluster with a 253.

thanks in advance.
cheers

 

[mr j-man]

check all your ground terminations, i found a while back in mine it had the similar problem (temp) and it was a shitty connection to the body. as for the volts mine fluctuates between 12 &14v but this seems to be normal, i would replace the reg.... they arent that exe.... remember the "big 3".

 

[DerekP]

Sounds like an earth leak.

 

[markovr]

I found a couple of dodgy solder joints in the cluster on mine and the way the threaded stud of the actual gauge contacts with the pushed in lug on the circuitboard looked dodgy too so I got the lug out and pushed the 2 contacts closer together and pushed it back into the board...the volt gauge never read as high as it does now...it used to jump all over the place but now it sits steady on a little under 14v when the engine is running. The temp gauge has a similar stud/lug setup too. The earth for the instrument cluster is under the right hand kick panel under a screw too so check it as well.