7.3 coolant temp sensor issue
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7.3 coolant temp sensor issue
Just bought a 2002 ford excursion 7.3 auto and I've been having two issues one with the coolant temp sensor not reading temp and the transmission temp sensor reading warm while cold. I've changed the sensor to 3 diffrent ones a grey conector and black connector as well as the ford part(3f1z12a648a) which is grey and my harness has a a grey connector for the coolant the black would read hot and the grey would show negative values on and eventually show some positive but only 10 degrees and would just barely even indicate on the dash and on the scanner I know the guage is fully working and I'm seeing 5v on the connector I was wondering if anybody whose has had this problem or similar help me out or point me to a post that might be really close thank you
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I agree I read some other forums based on on color the temp sensor it changes wiring where I can see that but don't really know Some were saying that they might both ground together and could be a bad ground but wouldn't know where to start. Appreciate the reply
Cargo Master
Joined: Nov 2017
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From: Rock Hill, SC
This is the water pump sensor that you are working with? There are 2 on the 7.3, one for the dash gauge, and one for the PCM.
When I replaced my water pump and some other parts, I also replaced the coolant sensor on the water pump. The dealer sold me the one for the PCM, it never allowed the dash gauge register.
The correct part number for my 7.3 as read from the OE one is F65F-10884-AA.
When I replaced my water pump and some other parts, I also replaced the coolant sensor on the water pump. The dealer sold me the one for the PCM, it never allowed the dash gauge register.
The correct part number for my 7.3 as read from the OE one is F65F-10884-AA.
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Yes I'm replacing the one on the water pump the one with the part F65F-10884-AA is the plastic is black and itll only read hot my connector to is grey they aren't compatible from what I've tested with two of the same off brand ones similarly some people have had the same luck. Thanks for the reply
Cargo Master
Joined: Nov 2017
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From: Rock Hill, SC
The difference could be that I'm a 2001, and you are a 2002, you should have the newer electrical platform, IE: no GEM under the dash mounted behind the lower interior fusebox.
So this could make sense regarding the plug connector color.
So this could make sense regarding the plug connector color.
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Lead Driver
Joined: Apr 2011
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From: Northern California
have you looked up the specs to test the actual sensors with a ohm meter ?
i tried to make sense of your this color and that color sensor but as far as I know those colors are not a standardized means of identifying anything other the one vendor likes grey plastic and the other vendor buys a different plastic, the OEM harness supplier likely used the color Ford speced for assembly line identification purposes but doubtful to unlikely any of that carries over into the service parts side of the industry.
what is standardized is temp sensors are a thermoresistor and physics dictates the resistance in them. so grab a multi meter and get a reading then compare the reading to the ambient temperature on a chart. you will then know if it is a sensor issue.
i tried to make sense of your this color and that color sensor but as far as I know those colors are not a standardized means of identifying anything other the one vendor likes grey plastic and the other vendor buys a different plastic, the OEM harness supplier likely used the color Ford speced for assembly line identification purposes but doubtful to unlikely any of that carries over into the service parts side of the industry.
what is standardized is temp sensors are a thermoresistor and physics dictates the resistance in them. so grab a multi meter and get a reading then compare the reading to the ambient temperature on a chart. you will then know if it is a sensor issue.
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Tuned
Joined: Mar 2019
Posts: 295
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From: Eastvale Ca
on my 2000 7.3 schematics show the water temp sensor goes to the gauge only, the pcm reads oil temp, my scanner and cts2 can only access engine oil temp, i plan on adding a coolant temp sensor to my cts2
Cross-Country
Joined: Aug 2014
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I'm assuming you figured out which replacement part works? I'm having the same issue, I cannot find a replacement sensor that reads the same resistance as the part being replaced (f65f 10884-aa) I've seen multiple forms discussing this issue with the 2000 and 2001s, but nobody ever posts the resolution or the final part they used to fix the issue
Tuned
Joined: Jun 2003
Posts: 465
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From: Connecticut
If I recall correctly, coolant temp input to the ECM was only available on manual transmission trucks. My 2001 PSD Ex, for example, does not have it.
The coolant temp sensor that's on my engine is for the idiot light "gauge" on the dash, which for the most part I've found to be pointless. My engine was running hot in 2021 but that coolant gauge resolutely stayed solid at mid-way across the dial. I only figured out due to the increasingly high oil temps I was seeing on my Edge display.
As such, I'd personally not worry too much about a resistance difference.
The coolant temp sensor that's on my engine is for the idiot light "gauge" on the dash, which for the most part I've found to be pointless. My engine was running hot in 2021 but that coolant gauge resolutely stayed solid at mid-way across the dial. I only figured out due to the increasingly high oil temps I was seeing on my Edge display.
As such, I'd personally not worry too much about a resistance difference.
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