The instrument panel housing itself has nothing to do with your problems. The pcb controls the gauges etc and the speedo is nothing to do with the electrics on the instrument panel.
Check that the square end of the speedo cable is still secured in the nearside wheel grease cap
Check that the speedo cable is securely fitted in the back of the speedo
If both are ok then the cable could have gone
Also remove the speedo and check the plastic cogs haven't broken
As for the temp guage thats powered by the pcb.
Are the connections clean on the wiring plug on the back of the instrument pod?
Try cleaning the connections beneath the 3 nuts that hold the fuel gauge to the pcb and housing
Check the integrity of the tracks on the pcb
Check the earth crowns on the nearside behind the fusebox
If all else fails then it's time to join the ebay queue for 2nd hand parts bearing in mind there are different pcb's both early (vertical plug) and late (horizontal plug) petrol as well as diesel. Also there are early and late fuel and temp gauges.
Try breakers if you need bits like Billy739, letshaveabus and
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