How to check engine temperature warning lights

[August65C10]

Hi Everybody
I'm new at this forum. First thing I would like to do is to apologize for my writing. I'm from Buenos Aires, Argentina, so english is a foreign language for me. So please forgive my mistakes.
A few days ago I purchased a 1965 Chevrolet C10 stepside with a 230 CID 6 cylinder engine.
As temperature gauge, this truck has only two lights, green for cold engine and red for too hot engine. My doubt is about how to check if the red light is working.
When I turn the ignition key clockwise to the contact position, green light lights up and so does oil and generator light, but the red light doesn't. And if I turn the ignition key all the way counter clockwise the red light lights up, but the green one does not.
My question is: Is that the way I´m suposed to check the red light? First I have to turn the ignition key all the way counter clockwise and check the red light, then turn the ignition key clockwise to the contact position and check green, oil and generator lights, and finally start the truck? Or something is not working as expected?
Many thanks in advance, your help will be much appreciated.

Augusto

[bloo]

Something is not right.

There should be a sending unit on the engine with 2 pins. If you unplug it, with the key on, and you ground one wire, the hot light should come on. If you ground the other wire, the cold light should come on.

When you turn the key all the way to start, the hot light should come on to check the bulb. I don't think the cold light ever gets checked.

The sockets for the bulbs can sometimes get stuck in the wrong holes in the instrument cluster. The hot light has a red socket and the cold light has a black one.

Also, have a look at this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789198
On that truck the wiring harness was wrong.

[August65C10]

Originally Posted by bloo

Something is not right.

There should be a sending unit on the engine with 2 pins. If you unplug it, with the key on, and you ground one wire, the hot light should come on. If you ground the other wire, the cold light should come on.

When you turn the key all the way to start, the hot light should come on to check the bulb. I don't think the cold light ever gets checked.

The sockets for the bulbs can sometimes get stuck in the wrong holes in the instrument cluster. The hot light has a red socket and the cold light has a black one.

Also, have a look at this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789198
On that truck the wiring harness was wrong.

Thanks a lot bloo!
I didn´t know that the hot light should be checked while cranking the engine. Something is not correctly wired. The post on the link has great info too. I´m going to check the wiring today. Thanks!