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#1
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Temperature Idiot Light Operation
New to me 67 Catalina has an early 70s 400 in it. No gauges just idiot lights. When the ignition is turned to ON I get the oil light but nothing else.
I disconnected the water temp sensor line at the engine and ran it to ground. Turn the ignition ON and now I get the TEMP light also as expected. My question: Isn't the TEMP light supposed to come on prior to engine start as a check that the idiot light is working? If so, how is that sensor supposed to be wired? I hate being left to guess if the bulb is still good every time I start the car. Will add temp / oil pressure / voltage gauges in the future but until then...
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Mark Las Cruces NM ___________________________ Current Project: '67 Catalina Convertible 400 4-spd |
#2
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The circuit to the temp sensor is grounded by the ignition switch in the start position to test the bulb.
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Lee Peterson ------------- "I didn't expect a kind of Spanish Inquisition...!" '69 Cameo White RA III Judge, 4 speed, owned since 1977 -- my first car. |
#3
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Thanks. Now off to find the ground lead on the ignition switch....
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Mark Las Cruces NM ___________________________ Current Project: '67 Catalina Convertible 400 4-spd |
#4
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I believe it's internally grounded. Make sure the switch housing is grounded to the dash
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Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express |
#5
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If the oil light comes on, the ignition switch ground is not the problem. You need a new sensor
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#6
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I don’t think so…the oil pressure light comes on with the engine off because there’s no oil pressure and the oil pressure switch is closed. The temp light comes on in the start position because the ignition switch grounds the circuit.
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Lee Peterson ------------- "I didn't expect a kind of Spanish Inquisition...!" '69 Cameo White RA III Judge, 4 speed, owned since 1977 -- my first car. |
#7
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While troubleshooting this, I saw that the oil light comes on with the key in the ACC position.
So is it mis-wired to the ignition?
__________________
Mark Las Cruces NM ___________________________ Current Project: '67 Catalina Convertible 400 4-spd |
#8
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Both switches are Gradual Grounds. If the lights were gauges, they would be actual volt meters with oil pressure or temp in degrees.
So with key on, or acc on some circuits you get 12 v through the Ign,FUSE box, to the gauge or idiot light. other side to the sending unit that grounds it. The Fuel gauge works the same exact way, the sender is a gradual ground. You can have a "dim" temp light . This isnt rocket science.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#9
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Quote:
__________________
Lee Peterson ------------- "I didn't expect a kind of Spanish Inquisition...!" '69 Cameo White RA III Judge, 4 speed, owned since 1977 -- my first car. |
#10
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Quote:
which was the point I was trying to make for troubleshooting. A "real" temp switch can give you a dim light... thats not really on or off, and showed up at my Dealership a couple times a summer. Your point is well taken, was just trying to simplify.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#11
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I get the whole theory behind these.... but the oil light should NOT come on with the ignition in ACC position. Must be miswired, correct?
__________________
Mark Las Cruces NM ___________________________ Current Project: '67 Catalina Convertible 400 4-spd |
#12
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That’s correct. I wonder if the “run” and “accessory” wires are switched at the ignition switch. Is the ignition coil also hot in accessory? The alternator field? They shouldn’t be.
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Lee Peterson ------------- "I didn't expect a kind of Spanish Inquisition...!" '69 Cameo White RA III Judge, 4 speed, owned since 1977 -- my first car. |
#13
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Quote:
I would be more apt to look at what has been done, vs a ignition switch. Not many would rewire that connector that plugs into the Ignition switch.
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"The Future Belongs to those who are STILL Willing to get their Hands Dirty" .. my Grandfather |
#14
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Quote:
__________________
Mark Las Cruces NM ___________________________ Current Project: '67 Catalina Convertible 400 4-spd |
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