Coolant Temp Sensor Disconnected (?)
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Coolant Temp Sensor Disconnected (?)
Okay, here goes: In the process of trying to diagnose some engine issues with my son's 96 LT1 via telephone, he told me that the connector to the CTS in the PASSENGER SIDE head has NO WIRE coming from it.
Just the sensor and connector - but NO wire. So I asked if both gages are working and he verified both the digital AND the analog gages are working.
I can't understand how that can be; wire disconnected but gages work.
Any thoughts on this?
Thanks,
Jake
Just the sensor and connector - but NO wire. So I asked if both gages are working and he verified both the digital AND the analog gages are working.
I can't understand how that can be; wire disconnected but gages work.
Any thoughts on this?
Thanks,
Jake
Race Director
Joined: Jan 2002
Posts: 12,263
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From: O'Fallon Missouri
Hmmm, that doesn't make sense. With the temp sensor in my 94 disconnected, the analog gauge does not work. There is only one wire for the coolant temp sensor in the head. Maybe he saw one and thought it needed two?
Last edited by STL94LT1; Aug 1, 2010 at 03:15 PM.
Race Director
Joined: Apr 2003
Posts: 17,700
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From: moraga ca
On the earlier C4s, there were 2 temperature sensors, one for the dash and one for the ecm. The one in the head was for the dash. The one in the front of the manifold was for the ecm. Not sure about the LT1s.
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Well, he's at Ft. Lee in VA and I'm in TX so I can't actually SEE, but he said he ran his hand over the connector and reported NO wire.
I had him check both TEMP GAGES and BOTH are reporting temps, so I'm confused, too. I tried finding something in the FSM on this didn't find anything that would help. I was pretty tired at the time so that accounts for it.
I suspect the single wire (he and I both know it's only a one-wire connector) is for the analog gauge, not the digital, but haven't found anything, yet, to confirm that.
So the question remains "How could the gages be working with that sender wire NOT connected?
Oh, BTW, LTs have one sensor in the water pump that is used by the PCM for it's operation and there's a SENDER in the Passenger side head is for the dash gages. I don't know if the PCM even accesses the head SENDER.
From my reading on this, the one in the head is a SENDER, as opposed to a SENSOR.
Strange.
Jake
I had him check both TEMP GAGES and BOTH are reporting temps, so I'm confused, too. I tried finding something in the FSM on this didn't find anything that would help. I was pretty tired at the time so that accounts for it.
I suspect the single wire (he and I both know it's only a one-wire connector) is for the analog gauge, not the digital, but haven't found anything, yet, to confirm that.
So the question remains "How could the gages be working with that sender wire NOT connected?
Oh, BTW, LTs have one sensor in the water pump that is used by the PCM for it's operation and there's a SENDER in the Passenger side head is for the dash gages. I don't know if the PCM even accesses the head SENDER.
From my reading on this, the one in the head is a SENDER, as opposed to a SENSOR.
Strange.
Jake
Pro
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Okay, here goes: In the process of trying to diagnose some engine issues with my son's 96 LT1 via telephone, he told me that the connector to the CTS in the PASSENGER SIDE head has NO WIRE coming from it.
Just the sensor and connector - but NO wire. So I asked if both gages are working and he verified both the digital AND the analog gages are working.
I can't understand how that can be; wire disconnected but gages work.
Any thoughts on this?
Thanks,
Jake
Just the sensor and connector - but NO wire. So I asked if both gages are working and he verified both the digital AND the analog gages are working.
I can't understand how that can be; wire disconnected but gages work.
Any thoughts on this?
Thanks,
Jake
He (your son) says that both analogue and digital gauges are working.
I assume he has the C68 AC with digital readout?
Did he just look at the digital readout, or did he actually press and hold the fan up/down buttons, followed by pressing the up button to number 16 and then the auto button once, to find out the engine temp (Celsius)?
If "the digital gauge works", what readout did he get?
If nothing connected on either sensor, it can´t be much more than the outside temp, if he didn´t press any buttons.
Racer
Joined: Jun 2010
Posts: 402
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From: Tabernacle NJ
The sender in the passenger head controls nothing but the analog gauge on the dash. The one with the needle, not the one that you can show on your speedometer screen. to clear any possible confusion. If that gauge works, then the wire is there and connected. Its probably just bent down and tucked under the sensor. It's then routed behind the exhaust manifold, so I could understand it being hard to see.
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The sender in the passenger head controls nothing but the analog gauge on the dash. The one with the needle, not the one that you can show on your speedometer screen. to clear any possible confusion. If that gauge works, then the wire is there and connected. Its probably just bent down and tucked under the sensor. It's then routed behind the exhaust manifold, so I could understand it being hard to see.
Racer
Joined: Jun 2010
Posts: 402
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From: Tabernacle NJ
If I recall correctly the wire is supposed to be (dark)green, but mine came wrapped in its entirety in grey/black thermal insulation, due to the proximity of the exhaust.
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Anyway, the wire must be connected and since he's getting temp readings I'm not going to concern myself about it right now. Next time he's under the car I'll have him look very carefully for the wire.
Thanks for the responses.
Jake
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
The sender in the passenger head controls nothing but the analog gauge on the dash. The one with the needle, not the one that you can show on your speedometer screen. to clear any possible confusion. If that gauge works, then the wire is there and connected. Its probably just bent down and tucked under the sensor. It's then routed behind the exhaust manifold, so I could understand it being hard to see.
Jake
