HELP! I have a 2000 Dodge Grand Caravan SE 3.3L. I replaced the radiator (crack in neck) and the water pump and when I was done I had an issue with the temperature gauge as it barely moved. When I turn the key, the gauge will move slightly but no matter how hot the engine gets the gauge does not move. I noticed that when I disconnected the engine coolant temperature sensor the radiator fans turn on regardless if the engine is hot or not. I’ve looked in my repair manual and on the internet and nothing available on this subject. Any suggestions and help would be greatly appreciated……….. Thanks so much.

 

It's possible you have an actual temperature issue and not a gauge issue. When you replaced the rad and water pump did you also replace the thermostat? If the thermostat is stuck open the engine will take forever to get to normal operating temp.

Also when you disconnected the ECT sensor did you replace it? And did it affect the gauge reading when it was disconnected? It's also possible that the vehicle has a separate sending unit for the temp gauge - you would need to check your repair manuals to see if it has this.

 

Hi Kuyabribri,


Thanks for the reply!
When I replaced the radiator and water pump, I also replaced the thermostat. I ran the car and noticed the thermostat appeared to work correctly. After warm up the upper hose became warm and I could feel flow through the line and the heater was warm (normal for that car). Also, I noticed after cool down fluid drain into the overflow tank via the radiator cap and tubing. I did not replace the ECT sensor but I did notice that when I detached the wiring to the ETC sensor the electric radiator fans activated. I tested it on a cold and warm engine and the fans came on regardless of the temperature of the engine. I looked in my repair manual (Haynes) and I do not see anything for a separate temperature gauge sensor. I do notice a sensor behind and below the ETC sensor but I am unable to find any information on it. I have looked all over the internet and information is hard to come by. Any additional assistance would be appreciated. Thanks for your interest.

 

This is just a guess but it's possible that the fans turn on if the PCM detects open circuit at the ECT sensor as a failsafe.

If the second sensor is located fairly close to the ECT sensor it is possible that that is a sending unit for the dashboard temp gauge. I don't know enough about your model year to be able to tell you if that van had a separate ECT sensor and temp gauge sending unit.

 

Thanks. I tried looking for information on the temp sending unit but I was unsuccessful. It seems that year is a cusp year. Lots of information of pre 2000 and post 2000 Caravans but the 2000 year is tough to get info on. Thanks for the help. I may try changing the sensors but I hate throwing darts at a dart board blind...LOL. Thanks again.

 

If the "pre-2000" information you're finding is about 1996-1999 models, it is likely applicable to the 2000 as the 3rd generation ran from 1996-2000. Information on 1991-1995 (2nd generation) or 2001-2007 models (4th generation) is less likely to be directly applicable but may still be useful.

 

I just wanted to give you a update on what happened with my Caravan. I changed the temp. sensor for $18.00 (Advanced Auto) and that did the trick. Apparently that one sensor not only controls the fans but also is a sending unit for the dash gauge. Thanks so much for taking the time to assist me with this problem.
Ps. The other sensor I mentioned that was located behind the temp. sensor is a cam shaft sensor. That was fine.