italian volts gone haywire

[kartone]

1980 gtv: preamble, have installed relays at ignition switch and low/hi beams.
With the key turned to accessories or with engine on when using the indicators stalk the ignition light comes on and the RPM, fuel level, oil pressure, coolant temperature gauges switch off; if however the hazard switch is used, no issue.
The use of the indicators stalk ONLY affects the gauges listed and ignition light, EVERYTHING else functions properly.
Battery voltage OK, wiggled the indicators stalk to no avail. What's next?

[jazig.k]

Can you get onto a second stalk assembly? Maybe try another assembly if you can find one to rule out internal issues with the stalk.

[colcol]

Check your earth wires and positive leads going into your instruments, a poor connection can stop the gauges getting their full amount of juice, they have enough when normal, but when another electrical component is switched on the current goes to the good connection.
Have a similar problem with the 33, when you put the wipers on, it steals current away from the Speedometer and Revcounter and they work erratically, Colin.

[kartone]

colcol, the leads & connectors physically appear in good order but tonight I will check voltage drop across the connectors

[ACP]

Also check the ignition switch... Just in case... Are the head lights aok, no dimming?  Usually the ignition switch would kill the engine and lights with the switch still on(typically at the most inconvenient time,  e.g. At night passing other traffic)...

[Mick A]

1980 gtv: preamble, have installed relays at ignition switch and low/hi beams.
With the key turned to accessories or with engine on when using the indicators stalk the ignition light comes on and the RPM, fuel level, oil pressure, coolant temperature gauges switch off; if however the hazard switch is used, no issue.
The use of the indicators stalk ONLY affects the gauges listed and ignition light, EVERYTHING else functions properly.
Battery voltage OK, wiggled the indicators stalk to no avail. What's next?

Maybe look at the hazard switch itself.