If all the instruments are out, it's the fuse. Note that you may also have no cruise control OR BRAKELIGHTS!!!

Check the fuses -- chances are they are all getting white and corroded, replace all the aluminum strip ones (white body ones) and any others that look less tha perfect, they crack with age.

I had this happen yesterday on the way home from work. I heard a funny whirring noise (turned out to be bad reception on the radio), looked down and had ZERO oil pressure! Pulled off at once and stopped the engine, checked the oil, everything was fine. Since it was running normally, I figured I HAD to have oil pressure, so idled it with the filler cap off, and sure enough, the cam was throwing plenty of oil. Looked again and all the instruments were dead -- tack, temp, oil pressure, fuel gauge. Swapped in a spare, works fine. I noticed on the fuse box label that the brake lights are on that fuse too -- explains why I was nearly rear ended on the expressway....

If the fuse is OK, check to make sure the wire to the temp sensor is connected. If you ground the wire, the guage should go full hot -- if not, either the wire or the guage is bad.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!