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Dear cedarwood,
Hope you're well. Solder joints can develop micro-cracks. These are too small to be seen with the unaided eye, or even with the help of a magnifying glass. The only way to cure a micro-crack is to re-flow the solder on each joint. Using a soldering iron with no more than 30 watts (20 watts is better), touch the tip to each joint, for 1-2 seconds. When the solder changes color - from dull gray to shiny silver - the solder has liquefied. This closes any micro-crack. The blue flexible circuit card is plastic, so using a low-wattage soldering iron reduces the risk of melting the plastic, and ruining the circuit card.
Because most of the indicator bulbs on your instrument cluster do not light, I suspect a faulty ground. I do not have a wiring diagram for a '95 940. On the '94 940, the cluster is grounded at a plate, behind the kick panel, on the door-side of the passenger's footwell. Behind this panel is located the engine computer. I do not recall - but would guess - that access to the ground plate does not require removal of the engine computer.
The ground plate's terminal can be cleaned with ultra-fine steel wool. A small piece of ultra-fine sand-paper (600 grit) can be used to clean the contact points on the ground wires' spade terminals. You might want to coat these contacts with a thin coat of di-electric grease. When the cleaned connectors are re-joined, they will cut through the grease, to make a connection. The grease coating will keep air-borne humidity away from the metal. The reaction of the metal, with the humidity, forms oxides. These oxides - corrosion - do not conduct electricity.
Do not assume because the connectors look "clean", that they are in good order. A layer of corrosion, sufficient to break a connection, can be invisible, even when inspected under a magnifying glass. Clean each connector.
To trouble-shoot electrical problems, it is necessary to have an electrical test light - which shows you if power is present - or a basic multi-meter. A multi-meter can help you find breaks in wires, and know how much energy is present, at a given point on a circuit.
I'd guess cleaning the ground for the cluster will cure the problem. If not, post back.
Hope this helps.
Yours faithfully,
Spook
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