Coolant Temperature Gauge Always Stays In Cold Position

Posted in Ignition Systems | Asked on Aug 7, 2010

One month ago, the temperature gauge of my 1996 Ford aerostar(3.0L) will move to normal after 20-minute driving. Now, the gauge always stayed at cold position even when I short circuited the coolant sensor connector to engine ground. I replaced the two coolant temperature sensors. The engine code is still P0118. When the ignition switch was turned on, the voltages measured were:(1) 4.0 volts measured between the one-wire coolant sensor connector and engine ground. (2) 2.8 volts measured between the green wire of the two-input sensor connector and ground. (3) 0.1 volts measured on the white wire of the two-input coolant sensor connector and ground. When the ignition switch was turned off, the resistance measured were: (1) 45 Ohms measured on the one-wire coolant sensor connector and ground (2) 14K Ohms measured on the green wire of the two-wire coolant sensor connector. (3) 0.1 Ohms measured on the white wire of the two-wire coolant sensor connector and ground. Any idea will help.

There are 6 Answers for "Coolant Temperature Gauge Always Stays In Cold Position"

  1. JOHN K says:

    stuck open thermastat

  2. mike g says:

    check the gauge for a good ground on the imprinted circuit board,also add a manual gauge just to see what temp youre at

  3. Anthony A says:

    Since you said you are sure the sensor is good, there are a few other possible issues:

    low coolant, stuck/failed/improperly installed thermostat, thermostat with incorrect rating, air bubble, faulty gauge, short/bad wiring, faulty ecu.

    Good Luck!!

  4. Jolly says:

    Sounds to me like a simpler solution. First thing I’d check would be the thermostat…chances are it’s stuck in the open position so that the coolant is constantly circulating.

  5. fmhguitars says:

    The coolent temp sensor does not control your guage the coolent temp switch does. It is a single wire unit. You will have to hunt for it. It may be around the thermostate ot water pump area. you may have to buy a manual at auto zone for location. when you do find it, turn on the key and ground the wire, the guage should go all the way to hot.

    Coolent temp sensor controls the amount of fuel when engine is cold, takes the place of the old fashsion choke.

    Some engines have two temp sensors thats why you may need to get amanual.

    If you feel as though you have the right temp switch and still can’t get the guage to move you will now have to start getting into your dash, which as you know is not going to be a lot of fun.

    Sincerely yours,

    Fred M. Hunter

  6. The Speedo Repairman says:

    Hi George.

    The Temperature guage has a little controlling board in the Instrument could be bad.

    If you short the wire to ground or input a good ohm signal and nothing happens; the the problem is in the guage and/or wiring.

    Remove the instrument cluster and check the signal wire for continuity. The guage should be powered with 12 volts and have a good ground also.It should be very easy to troubleshot with a good multimeter.

    I hope this helps. Good luck!

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