What wires can I splice to Keep Rad Fans "ON"

[Rolm]

What wires can I splice or join to keep the rad fans on at low speed. The dam fans will not come on unless the AC is on. I did replace the temp. sensor at the front of the engine No Luck. It's a 99 3.8

[bigpoppabear]

Originally Posted by Rolm

What wires can I splice or join to keep the rad fans on at low speed. The dam fans will not come on unless the AC is on. I did replace the temp. sensor at the front of the engine No Luck. It's a 99 3.8

Hey Rolm,

Did you find a solution to this problem. I'm having the same problem. Damn car won't stop running hot even after putting in new radiator, water pump, sensor, hoses, head gaskets.

[inafogg]

best to start new thread

[Ruley73]

Originally Posted by bigpoppabear

Hey Rolm,

Did you find a solution to this problem. I'm having the same problem. Damn car won't stop running hot even after putting in new radiator, water pump, sensor, hoses, head gaskets.

Did you replace the radiator cap?...thermostat? Are you using at least a 50/50 coolant/water mix?

[bigpoppabear]

Originally Posted by Ruley73

Did you replace the radiator cap?...thermostat? Are you using at least a 50/50 coolant/water mix?

Hello,

Yes a new radiator cap, thermostat, temp sensor and complete system flush, and use 50/50. The fans are not coming on. I unplugged the temp sensor plug and the fans stay running, but sustain below mid range temp. I just bought new relays, although I checked them before and they were fine, the cost is minimal to ensure they are working. Could the signal from the PCM be the problem with the fans not functioning during normal operation. Although, prior to the a/c heater control crapping out when the a/c was on the fans did run. With the a/c off they do not. I'm going to check the resistance on the temp sensor and wiring continuity and see what comes up.

Any other ideas or guidance will be greatly appreciated.

[Ruley73]

Originally Posted by bigpoppabear

Hello,

Yes a new radiator cap, thermostat, temp sensor and complete system flush, and use 50/50. The fans are not coming on. I unplugged the temp sensor plug and the fans stay running, but sustain below mid range temp. I just bought new relays, although I checked them before and they were fine, the cost is minimal to ensure they are working. Could the signal from the PCM be the problem with the fans not functioning during normal operation. Although, prior to the a/c heater control crapping out when the a/c was on the fans did run. With the a/c off they do not. I'm going to check the resistance on the temp sensor and wiring continuity and see what comes up.

Any other ideas or guidance will be greatly appreciated.

How hot is it running and what temp sensor are you referring to? The engine coolant temp sensor is located more toward the back (near firewall) side of either engine (3.5L and 3800) engine under the throttlebody; not the front. The only other temp sensors are the ambient air sensor (located in front of the radiator, provides outside temp reading for climate control unit) and the intake air temp sensor in the air intake.

[bigpoppabear]

Originally Posted by Ruley73

How hot is it running and what temp sensor are you referring to? The engine coolant temp sensor is located more toward the back (near firewall) side of either engine (3.5L and 3800) engine under the throttlebody; not the front. The only other temp sensors are the ambient air sensor (located in front of the radiator, provides outside temp reading for climate control unit) and the intake air temp sensor in the air intake.

Hi ruley,

The coolant temp sensor located just below the thermostat. The engine is a 3800 series II. I'm changing it out today. When I disconnected the terminal from the coolant sensor the fans did work.

I'll post the results. Thanks for your reply.

I also am loosing coolant. On the 98 3800 it only has one plastic 90 deg ell from the tension pulley housing to the intake which I changed when I put new heads on. The other seals for the heater hoses are copper adapters that slide into the pulley housing and seal with Orings (not found in local auto stores) although the two for the heater hoses were not leaking they need to be changed now that i took it apart. The one (1) 90 deg elbow that connects the housing and intake although new does not fit tight as it should in my opinion so I'm going to get a GM replacement. The other housing to head connection is a nipple from the housing which is cast into the housing that has an oring seal that slides into the head. I changed that oring when I put new heads on and it fits tight. I'm thinking the slight leak the car has must be coming from the new plastic 90deg. elbow put on during the new head job. The oring fit from the 90deg ell to the housing is the sloppy or loose fit. My fingers are crossed.

I'll post my results of todays work when done.

HAPPY FATHERS DAY to all the dads in the AF community.

[remark123]

My guess is that your leak is actually coming from the 90 degree coolant pipe. On my 3.8, I did not realize that part of the pipe actually boke off in the block, and I had to remove the idler pulley/housing and dig the plastic piece out of the block, then I got a good seal and was able to stop the leak. Good Luck!

[cougar214]

I'm having the same problem.My fans are not running and my temp is going a little above the half way mark.I have noticed my fans are not coming on.

I have also been using my A/C and coincidently my fans are also out.Could there be a link between the automatic function of the A/C and the fans cutting out?

A possible brainfart in the electrical system?


P:S I am also 800 miles away from home on vacation and I'm leaving tomorrow so I don't have the time to search all kinds of possibilities so if someone could please help me out I will give you my first born.Thanks guys.

[bigpoppabear]

Originally Posted by cougar214

I'm having the same problem.My fans are not running and my temp is going a little above the half way mark.I have noticed my fans are not coming on.

I have also been using my A/C and coincidently my fans are also out.Could there be a link between the automatic function of the A/C and the fans cutting out?

A possible brainfart in the electrical system?


P:S I am also 800 miles away from home on vacation and I'm leaving tomorrow so I don't have the time to search all kinds of possibilities so if someone could please help me out I will give you my first born.Thanks guys.

The first thing I could suggest to you on the road is stop at an autoparts store and replace the 3 relays. Should cost about 40 bucks and you can change them in the parking lot. See if that works first. If not, it is probably your coolant temp sensor which is a task to change. If you run into problems also make sure you have flow thru the thermostat. The relays would be my first shot for sure.

Let us know what happens.

[cougar214]

I'm not sure how many relays there may be.I know the book says one for the cooling fans.

What I did was swap the cooling fans relay for the ignition main relay and the car still started up so i'm guessing the relay is fine.The two cooling fan fuses are also fine.

I checked my rad cap and the coolant level censor and they are fine.

I have noticed the fans will come on as long as the A/C is on which makes no sense to me but ok.

If i have to drive home with the A/C on to keep it cool it's not a problem.It's summer anyhow.

[Mickey#1]

The low speed cooling fans don't come on until the engine temp is around 205. High speed kicks in around 215. This is all controlled by the PCM using input from the CTS (coolant temperature sensor).

If the fans come on with the A/C then the problem is probably the CTS or an inaccurate temperature gauge. If you have a muti-meter then you can check the resistance of the CTS with the lower part of the sensor in a pan of boiling water. You can also use a scanner to compare the dash gauge to what the PCM is reading.

[pfofit]

There are three relays and two 25 amp maxi fuses.

Maxi fuse 1 supplies source power to energize relay 1, both fans in low speed and the right fan in high speed, while maxi fuse 2 supplies power to energize relays 2 & 3 and the left fan on high speed only.

Low speed is achieved by connecting the two fans in series through contacts in relay 1 & 2.
Thiis results in each fan with 6 volts and turns slowly. If the fans are sticking, then 6 volts may not be enough to get them going. With the key out try spinning them by hand to see hard it is for them to move and how may spins you get.

High speed is done by activating relays 1,2 & 3, which breaks the series connection and applies full battery voltage to each fan.
Ac will command high speed fans. As well, as mentioned previously the PCM monitors the sensors and determines when low speed and high speed is required and for how long they remain running based on temperature.

To bypass the PCM, if you remove relay 1 an jumper out(with a wire that will handle 25 amps, say a #12) the contact in relay 1 socket, then both fans should run at slow speed if the fans, wiring and contact in relay 2 is ok. Make sure that you are jumping the relay contact pins only, which can be determined by deciphering the markings on the relay cover.

To avoid mistakes, sometimes with a fight, the covers on the relay can be removed and I'll plug the coverless relay back in and use something non-conductive to push the contact in.

Be aware that power is always present on one side of the contacts even with the key out and only pulling the 25 amp maxi fuses will kill it.
Cheers

[cougar214]

O'k.I am home from my vacation and now the fans are working again?

This is very strange.My temp is normal now and no idiot lights.Do you guys think maybe this problem has always been there and I haven't noticed because of the speed limits in my town?

In my town my speed limits are all over 45 mph.Where as the speed limits up north where I was are 25 mph.

Do you think my higher speed limit is allowing more air to flow through the radiator thus keeping it cooler?

But that doesn't explain why my fans are now working again.All I did was unplug the coolant temp sensor and started the car and low and behold working fans.I pugged it back in and the fans were still working.

Me thinks my car likes messin with me.

[LittleHoov]

It could have just been a poor connection I suppose. Unplugging the temp sensor should put the fans on by default, but they will run all the time.

Could be that unplugging and plugging the connection back in got rid of a little corrosion or something causing a bad connection.

I think the speed could definitely have a lot to do with it. Here is an except from a random article I found, and Ive always hear this before too:

To cool efficiently, the radiator must be clean, in good condition and receive adequate airflow. The radiator's front-mounted location ensures good airflow when the vehicle is in motion, but at speeds below 25 to 30 mph, additional airflow must be provided by the fan. If an engine has been overheating, the fan should be checked to make sure it is operating correctly.

Ive always thought the Intrigue could easily have airflow issues anyway because of its lack of grille (I know the air dam is supposed to push air through the radiator) but I know half of my air dam has been ripped off too....

I dont know what the weather was like on your vacation, but humidity also plays a role in how well a car can cool. We typically have high humidity here in Missouri, and the other day on one exceptionally humid day, my Jeep was running over 10 degrees hotter than it normally does, and that was at highway speed. I have a digital temp gauge so I was able to see how hot things were. It hasnt run that hot since, just that one day.