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Good evening to the forum. Not quite sure, just asking: Vehicle is a 1966 Oldsmobile Ninety-Eight. When cranking the car, as seen in the picture, all the warning lights except the 'HOT' light illuminates in the cluster. Grounding the dark green wire on the sender will allow the hot light to come on, so the wiring/bulb checks out. Is the reason the hot light does not illuminate because the metal strip is (obviously) against the 'COLD' contact in the switch, during the cold start, and there is no way thus for the hot light to come on? Thanking all in advance for help on a probably very simple answer. Regards, Howie.
Look in your 1966 Oldsmobile Owner Operating Manual. I don't have one for the "B" body cars. The one for the "A" body cars says that the "Hot" light should come on momentarily when starting the car to assure that it is operating correctly. (Page 13.) Your theory may be correct for the 98.
Last edited by Ozzie; July 20th, 2017 at 11:47 PM.
Reason: added information
Look in your 1966 Oldsmobile Owner Operating Manual. I don't have one for the "B" body cars. The one for the "A" body cars says that the "Hot" light should come on momentarily when starting the car to assure that it is operating correctly. (Page 13.) Your theory may be correct for the 98.
Thank you, should have thought of this, forest through the leaves syndrome at times, but I did prove my theory with a switch already out of a car.
Thank you, should have thought of this, forest through the leaves syndrome at times, but I did prove my theory with a switch already out of a car.
I don't know what you think you proved, but the switch has no relationship to the lamp test function for the HOT light. The ignition switch has a separate green wire with white stripe that provides ground to the HOT light in the START position only to test that lamp. The COLD light doesn't require this because the temp switch grounds that contact when cold and the light comes on anyway. The OIL light is the same way - there is no oil pressure at start so the sender is grounded and the light comes on. The GEN light also comes on normally at start since the alternator is not turning and therefore the field terminal on the regulator is grounded. Only the HOT light requires the extra lamp test wire from the ignition switch. This is shown in the wiring diagram in the CSM - at least it is in my 67 CSM. My 66 CSM isn't readily available at the moment.
I think you mean "forest for the trees," as in "can't see the forest for the trees" which means to be so enmeshed in the details that you can't see the big picture.
I think you mean "forest for the trees," as in "can't see the forest for the trees" which means to be so enmeshed in the details that you can't see the big picture.
Exactly! I am human, and do not profess to know it all, not in the least, so I am hoping what I observed was correct, nobody helped until now with an explanation. Thank you Joe for your direct answer as always. Now I understand and when health allows me to crawl around the car, I will start sleuthing for the fault. Thank you folks for the input.