1996 VW Citi Golf Carberator type Chico 1.3. Heat gauge not working / working only sometimes for brief period. Also struggle to start when hot. I replaced the coil with the electric box , radiator (it was leaking slightly) , thermostat , brass type heat sensor switch , tested the fan sensor switch at bottom of radiator , engine now is running cool and fan switch on when needed. No starting issues - also checked all fuses - except the relays were not checked. Only thing is heat gauge still not working. Any suggestions or tips.
The first thing I would try is to check that the connector from the loom into the back of the clocks is firmly seated. This can cause the kind of problems you are describing and they will usually occur only intermittently.