#1 Cooling Fans Not Working!!

Hello Folks,

It seems to me with all the overheating problems with Luminas, that for some reason the #1 cooling fans do not work (they work a lot of times with A/C on, which is correct).

The search I did of the forum seems to bare this fact out.

If I understand correctly: the #1 gets it's request from the ECT to the PCM to the fan relay under the hood.

So in these cases it looks like to me that the PCM is at fault.

I have a 97 Lumina 3.1, replaced intake manifold gasket at 105K and also have this fan problem of not coming on.


Solution?....How about adding a fused wire to relay for #1Fan, install a toggle switch for driver to operate manually when Temp. gauge starts to rise?


PLEASE, Any comments, other ideas?, Easier ways to rig wiring?

Thanks,
XTECH

My temp rarely budges with one fan running, is rock solid at 1/3 with both running (A/C on) regardless of the ambient temp.

If your temp varies that much, something is wrong...It's only supposed to run one for engine cooling....and then only when the temp exceeds a set point.

As I stated in my post, I believe the problem lies in the PCM, My #1 Fan does not come on at all, except when the A/C is on. This is why I'm getting the fluctuation on the gauge.

If you unhook your #1 fan, you might have the same symptoms.

XTECH

My #1 fan will not come on at all, max a/c or not. I have swapped the relays around to see if one was bad and it ran #2 just fine. Fuses looked fine also. I may have to use the toggle switch idea unless someone has a better solution.
Here in Houston, we have already seen mid 90's and still my temp guage read alittle below normal. Which is were she runs all the time anyway. I am just afraid when we see the 100's for summer, she might want to overheat.

mudbeast66,

From what your'e saying, it sounds like #1 motor is bad, try running a wire from the hot side of battery directly to motor, to see if it runs.

Sitting in traffic in 100 degree weather you need a back-up(switch)?

With the 100's coming to you there, you need to repair soon....don't you!!

Hope this helps.

Let me know what you find out..
In Virginia,
XTECH

Thanks for the info.
I just LOVE troubleshooting electrical on cars.
MMMMMMMMMMMMMMMM.

Sounds like your fan motor is bad, as stated before....the fans come on/off mechanically and are not controlled by the ecm as far as turing on/off. There is a temperature switch that works similar to a therostat where once it gets so hot, it opens the current sending power to your radiator fan motor. That is why, on hot humid days when you turn your car off, your fan may still run for a second or two, because your engine is still hot. There is another sensor, the coolant temperature sensor that sends data into the ecm and also controls the gauge inside the dash. This data is only used for ecm to configure fuel ratio, this does not turn operate the fan motors. So, if your fan is not kicking in, there are only a few possibilites, bad fan motor, faulty relay, or a faulty temp sensor(unlikely).

Well, I dove into the fan motor issue this weekend. I found out both fans work fine; i hooked the thought to be bad motor, direct to the battery and it ran just fine. Back when i noticed the fan not running, i checked the fuses and the relays. I swapped the relays around and both fans worked the same. So after finally digging in a little deaper, I can rule out a bad motor, relays, or fuses.
I ask this question to everyone, do I try to fix it the right way, find the real problem? Or do I fix it the way I know best, run a hot wire to the motor and put a switch in the dash to control the fan manually?
Let me know what you think.
Thanks in advance for your help.
Mud

Your issue may be the harness or wiring from the CTS to the ECM, or from the ECM to the fan relay. The same sensor is used by the ECM for fuel calculations and to operate the fans. If you don't have a CEL for the CTS, then that would basically rule out the problem being between the CTS and the ECM. You'll have to consult a wiring diagram to determine what wires send the signal from the ECM to the relay, as that is where I believe your problem lies. IF you decide to wire in a toggle, either wire it through the relay (to keep the toggle from having to supply all the amperage), or at least wire it to only have power when the ignition is on, so you don't forget it and kill your battery.

Sorry, what does the ECM, CTS, CEL stand for?

ECM= Electronic Control Module. This is the car's computer
CTS= Coolant Temp Sensor. This is the one that signals the computer that the engine has warmed up for fuel trim adjustments and to turn on the fans.
CEL= Check Engine Light. It's the warning lamp in the cluster (check engine or Service engine soon) that tells you the computer has a sensor out of range.

Sorry, I can be a DA sometimes.
Thanks for the insight.
Do you have an idea for a site that shows wiring diagrams?
Or do I go get a Chilton or Haynes? Which publisher is better?

I personally prefer the wiring diagrams in Haynes manuals, but it's a personal preference. You may try autozones website, they have repair info for many vehicles available on-line.

Will try that, thnx

'93 lumina euro. MY two cooling fans are new. Fuses and relays are good. Wire connections are solid and responding true. ECM was replaced [for other problems] but
still with same results for the c-fans. My temp. gage soars near super-nova
but no fans come on. Ahh but wait, once I push any A/C button and wala,
the fans come on. This is frustrating, specially during the winter time when
the A/C is not being used. Help, help please. Thank you in advance.

I had the exact issues you describe on a 91 grand prix and a 92 lumina.....both were bad temp switches. It was located behind and below the thermostat housing and a pain to get to. Not sure of the location on your year model but its worth looking into. Mine were both 3.1's btw. Good luck with it, your gonna need them working with summer just around the corner.

welp i am at the end of my rope. My fans are both operable however they are seeming to have an attitude and do not want to work continuously. I here a click that usually precedes the fans operation. ( i am assuming that noise is the relay). The fans both 1 and 2 spin about three times and stop. My car seems to be fluctuating in temp quite a bit. Add water every few days. No apparent leaks. Oil has good consistency and very clean exhaust for 158k. Strong motor and well maintenanced. Do you think the frequent loss of water could be due to a lack of cooling from the fans. Does the relay need 2 be replaced. Or should i just give up and pay sumbuddy who knows what the hell is going on?

welp i am at the end of my rope. My fans are both operable however they are seeming to have an attitude and do not want to work continuously. I here a click that usually precedes the fans operation. ( i am assuming that noise is the relay). The fans both 1 and 2 spin about three times and stop. My car seems to be fluctuating in temp quite a bit. Add water every few days. No apparent leaks. Oil has good consistency and very clean exhaust for 158k. Strong motor and well maintenanced. Do you think the frequent loss of water could be due to a lack of cooling from the fans. Does the relay need 2 be replaced. Or should i just give up and pay sumbuddy who knows what the hell is going on? radiator crack at top of composite. Just found it. Fans working as long as a/c is on. Hope i can fix the composite. radiators are expensive.