I've had an overheating problem for several months. It happens in city traffic but not on the freeway. I've determined that the fan works, replaced the relay anyway. The car doesn't boil over as it nearly always happens climbing hills in idle and traffic and I'm just about home. Also fan comes on when the car is parked and key is off. So it functions in that mode, so I test drove it yesterday and found that the gauge rose after driving around the city, pulled into my carport kept it on, opened the hood and the fan was not on. Once I turned the key off it then it came on.

I called the dealer and of course they want to look at it.... can't afford that, and asked what the different sensors or switches are for the fan, and it was like pulling teeth to get an answer. The only guess he had was maybe a fan timer switch. That seems to make sense.

Can anyone give me some advice as to where that is located or if there may be another reason or switch? The thermostat was replaced in April '10
by the dealer. The fan motor is 1 1/2 years old.

I acquired the car in April 2010, it has 185 k on it. Also had an oil change in Dec. and there is no evidence of coolant in oil.

rolling

 

When you start the car and turn on the a/c, do both fans turn on?

 

If it were a 4-cyl car, I know the fan timer dissappeared beginning in 1998. Also the 2nd fan switch dissappeared.

Pretty sure it's the same thing for a V-6.

 

Even if the fans are not working properly, I would check coolant level in radiator as precautionary step.

The V6 has a radiator fan control module under the right side of the dash. The module controls the fan relays via the thermo-switches. Your problem sounds like it can be a bad Thermo-switch A, wiring, or radiator fan control module.

Thermo-switch A (#14) located on thermostat housing. It sends a ground signal to the radiator fan control module when it reaches ~ 190 degree F, at the same time activating the fan relay which would start the fan operations, when engine is running. It should shut off around 180 degrees F. To check fan switch A, unplug the green electrical connector and jump the connector with a wire or small paper clip. Turn ignition to ON, fans should come on.

Thermo-switch B (#10) located on the left of the front cylinder head turns on the fans at ~ 225 degrees F. It grounds the fan switch B terminal in the radiator fan control module when engine is not running, so power is supplied to the radiator fan relay to turn on the fans.

#13 is temperature gauge sender and #15 is the ECT sensor for the ECM/PCM fuel/ignition data.

 

Hey redbull-1

Thank you so much for the diagrams. Will I get electricuted when I touch the wire to the paperclip to an engine part and turn on the key? My mechanical knowledge is better than my elec.! I really suspect that it is Thermo A... heard they fail often, and of course it's simpler and cheaper. Also I carefully watch the coolant in the radiator and tank.... no loss there. I checked the relay fuse today and it's fine.

Of the several responses here you had certainly read my description of the problem. We know the fan is good, we know it works after the car engine is off, we know it doesn't work when the car is hot in drive, idle and the gauge rises. Both fans come on when I turn on the AC. We know there is no boil over or leaks.... so it's getting narrowed down.

 

You won't get electrocuted. An insulated wire with the ends stripped off would be better; but, a small paper clip works fine. Don't use a big paper clip, as you don't want to make the connector terminals too big. Attach wire to connector first, then turn ignition to ON.

Just turn off ignition after you made the test, then remove the wire or paper clip.

 

Excuse that I'm electro-challenged. I want to make sure I have the concept here. If the fan runs when I do this, it means that the Thermo A is in the way of completing the circuit, in otherwords "dead", right?
Now the green wire(hot)? when connected to the clip or wire I use needs to be grounded to "where" to make this happen? To the cylinder head or anything metal, engine or body, nearby? Can a piece of insulted wire be any thickness?

I will do this test on Friday but hope to hear back from you before I try. Also do you know the correct socket size to remove the ThermA if it is bad?

Ty.. Redbull-1

 

Unplug the connector to #14 without the key in the ignition. Take a piece of wire and each end into the two connectors. You want the piece of wire to connect both wires.

When you turn the key on and start the car, both fans should run.

My suggestion about turning on the a/c is a quick test to determine if the electronics for both fans are working.

EDIT... Here is the picture:

 

I believe the switch is open when the coolant temperature is below 190 degrees and closes when it it higher than that. The closed switch would activate the fan. By jumping the connector, it would be as if the switch was closed.

You would disconnect the green 2 pin electrical connector and connect a wire or small paper clip to the 2 terminal holes on the connector. Then turn ignition to on. Any wire or paper clip that is not too thick will work, you don't really want to widen the terminal holes on the connector.

I believe the socket or wrench size for Switch A is 24 mm.

 

Redbull-1 & PAHonda
I did the paper clip as you both explained and the fans both run! You're instructions made it very easy. The wires terminal as you may know are enclosed in a special plastic sleeve that slides onto the top of another plactic cap that is part of the ThermA. It clicks in place. The cap on the unit, is partially broken off around the outer lower edge. Would that be why the therm is no good? Also is it part of the ThermA or is it something extra that I must order so it all fits together? I can't really explain better what it is..... you probably are familiar with this this setup.

I'm really happy that this may be the answer to my overheating problem. I will order the new one right away. If you have a picture of what I'm talking about send it along please. I guess it could be called a fitted jacket for the unit. Ty so much.