Classic/Antique Car Repair: electrical on Olds, coolant temperature switch, olds delta 88

Question
70 Olds delta 88. I have redone the cooling system since I had the A/C now working, seems to have been overheating, I think I have that problem corrected, anyway I do not know if the hot idiot light is working, I have jumpered the two wire connector at the temp switch, nothing. I checked with volt meter each leg to ground, both are at the same potential, I'd have thought one would be 12 volts, the other to the light. I have a shop manual, but I cannot make out the diagram with even a magnifying glass. Wireing is original, is there something else I should be looking for? I do not suspect anything other than original wireing from the factory on this car. Thanks.

Answer
Kevin, if my memory serves me right the coolant temperature switch on your car is a single wire switch. It should be located on the intake manifold right behind the thermostat housing. There is a coolant temperature switch on some of these car on the front of the left cylinder head that has two wires, for the emissions system. The wire to the idiot light temperature sending switch receives a 12 volt signal through the bulb in the dash. When the temperature gets over 220 degrees or so the switch closes and the idiot light comes on. Take a test light and jumper each wire to ground. The test light will prevent a short but the one that turns on the idiot light when jumpered to ground through the test light should burn dim. Good Luck
Brad