1999 mercury g/m 4.6 where is the temp sending unit for the computer not the dash gauge i have manual but it only shows dash sending unit
Country: United StatesMake: MercuryModel: Grand MarquisYear: 1999Engine: 4.6
disconect gauge unit to see if it was the right one but it wasnt
Welcome and thanks for your question. My name is XXXXX XXX I am here to try and assist your with your question
You have a cylinder head temp sensor. The computer gets the temp of the head not the coolant. It is located under the upper intake manifold on the drivers side head.
Actually there is only one intake and you have to remove it to get to it. Ill send directions. Below you will see some blue words, click on the blue words, and a pdf file will come up and explain to you how to replace or get to it.
click here for sensor location and removal.
great my scanner says cyl head temp is only 61 degees f or is that normal
No it is not.
It sounds like it is unplugged or the wire harness is chewed up by a mouse under the intake manifold.
I have seen many times a chewed up wiring that goes to the sensor under the intake manifold. Mice tend to like to make there nest under the intake and chew on wires.
ok i will remove the manifold and check it out , thank you for the promptness
25 years experience working for Mercury Dealer. Master tech
what is the normal temp reading for this sensor on scanner
With the engine hot should read around 200 degrees, or the same as the tempature on the gauge.
ok when i start it it is 61 F. and goes to 74 f when the temp guage on dash is in the middle
That is to low should read engine temp hit. The computer goes into a fail safe mode around 70 degrees when the sensor is unplugged or the wires are faulty.