Dear oneeyeblind,

Hope you're well and stay so! According to the Volvo pocket data booklet - Cars (700,850,900), 1991-95 - a 3-1-1 code means the speedometer signal is absent.

Just because the wire is present, doesn't mean current flows. A layer of corrosion invisible to the unaided eye - just a few molecules thick - can disrupt current flow. Use an aerosol corrosion-removed on the contacts at both ends (cluster and ECU). Check any connectors - especially those in the engine bay - for corrosion.

Further, the blue-green flexible circuit card can develop micro-cracks. These can be found with use of volt-ohm-multimeter. Plainly great care must be taken when reflowing solder to close a micro-crack or when using a copper wire bridge over a break.

Hope this helps.

Yours faithfully,

Spook