tempature problem

[215marq]

Hi guys I am new to the forum I have a 98 mecury grand marquis gs. I only had it for 3 days now and the car has made major improvements but the biggest problem I have is my fans wont come on automatically and my tempature gauge reads hot if I drive at least one mile down the road. I currently have a toggle switch running the fan but i hate that so I was wondering if you guys can shine some light on my situation.

[cvpiftw]

check the relays?

[JVJ]

It may need a good flush!

[lucenti]

is your coolent leaving the reservoir ? i

[BlownMerc]

I the fan works but won't come on with temp or a/c, probably the relay. There is a separate low speed and high speed relay, low speed circuit protection is a circuit breaker, high speed uses a fuse. If neither is getting the job done, I would be suspicious of the PCM or cht sensor. Also, if the sensor isn't telling the PCM that the motor is hot. The gauge reads off of a coolant temp sensor, the fan control is monitored by the cylinder head temp sensor. So a problem with the cht could cause no fan but the gauge works and tells you it's hot.

Also, if it is overheating while moving down the road, it isn't (just) a fan problem. The air moving through the grille should be enough, and I believe the fans aren't operated above 35mph anyways. If coolant level is good, it could be stopped up radiator or headgasket problems. Usually a partially clogged radiator will not overheat sitting still but run hot at interstate speeds.

Good luck, hope any of this helps.

[Dragcity]

T-Stat stuck Closed ???

[TAKEDOWN]

Welcome to the site!

[215marq]

thanks for the input but i dont know where any of the relays or sensors are except for the one on the manifold the thing is the car doesnt run like it is over heating but i honestly dont know my antifreeze level is ok and my heat works so doesnt that mean my thermostat is ok

[O's Fan Rich]

Do you have a shop manual for your car?
If not, may I suggest investing in one?
They are a great aid in diagnosing service issues with a car. They also help you locate where various items can be found, for instance temperature sensors and fan relays.

[215marq]

i was looking at one of those and it is not really specific

[lucenti]

download owners manual from ford it's on page 142

[215marq]

ok guys I found out what was wrong with the temp gauge the coolant tenp sensor was bad I had tested the fan with the air condition on and it will come on but it will not come on when the car heats up on its on does anyone know when the fan is suppose to come on. I found out that the car is not over heating also the tempature is good I scanned the car.