Hi,

I am having an issue with the cooling fan on the radiator. This was first noticed by my wife who complained that the AC was no longer working.

Here is what I know:

1) AC Compressor works. Radiator Fan does not come on when AC button is depressed.

2) 20 amp and 40 amp fan fuses are good. Swapped relays in fuse box and all seem to be in working order.

3) ECT getting 5v, ground is good. Dash temp guage works. Coolant Temps seem correct when viewed through Scanner.

4) Fan does not kick on when ECT is disconnected (saw this as a diagnostic point on a youtube video, not sure if it applies to this model and year).

5) My Scanner (Thinkdiag) is bidirectional. Command On works for Compressor and Fan 1, but not Fan 2.

6) AC provides cool air when turned on and Fan 1 is commanded on. Refrigerant System pressures are ok, and not indicative of refrigerant leak.

I have not gotten the fan connector off to see if power is going to the fan when Fan 2 commanded on by my scanner, but will try this evening.

What else am I missing / need to check?

Thanks,

Tom

 

I did some more checking after my initial post.

7) Checking voltage at the fan connector resulted in the following:
3.3 V when engine running and AC engaged
3.3 V when engine running and Fan Control 2 commanded on via Scanner (I assume this is for the low speed setting on the fan)
14 V when engine running and Fan Control 1 commanded on via Scanner (I assume this is the High speed setting)
14 V when engine running and 20 amp fuse pulled. Also generated P0481 Code, Cooling Fan Relay 2 Circuit. DTC went away when fuse reinserted and car restarted.
I also plugged in the connector to the fan at the above conditions. No movement at 3.3V, Fan ran at 14V.

8) I bought a new ECT and plugged it into the wiring harness. No change to any data points from the old ECT. This could change once it is installed, which I will tomorrow.

So, is 3.3V too low for the low speed (fan 2) circuit? I noticed there was a radiator fan resistor in the wiring diagram, but I have not located it. IF 3.3v is correct for low fan speed, then perhaps the fan motor is failing, and only operating at the higher voltages.

What else am I missing / need to check?

Thanks,

Tom

 

On my L series cars, there are two speed motors and three fan speeds. They run the two fans in series on the low side for low. Probably why you see 3.3 volts. Then they use low in parallel and high in parallel for a total of three speeds. If one of the fan motors is bad or has a bad ground, that may be your problem. I had a bad body ground connection under the battery on my sedan. My horn quit working and it shared the same ground as the fans.

 

So, my thought process for further diagnosis is:

1) Clean ground points in engine bay. Although I am still getting good ground through both the fan connector and the ECT connector, it is a good overall preventive maintenance.

2) Locate Cooling fan Resistor. Test if possible. Replace if needed. I am having a hard time finding info on this device, but failure indicators for other fan resistors seem to be either cooling fan running continuously or not at all. Often with a blower motor resistor failure, that fan will only work at full speed, and not the lower speeds controlled by the resistor.

3) Test Cooling fan motor. Replace if needed. This setup is one fan only, but two would have made more sense. I can probably only do a resistance test, but I will need to find the go / no go resistance value is on the motor. There are only a few of these fans available new, but a new one should outlast the car.

4) If none of the above work, it is likely a wiring or ECM / PCM issue. I have the pin numbers from the wiring diagram, but I do not have a pin-out diagram for the PCM/ECM. If anyone has that, please share.

Of great help would be finding out the voltages on another 2.2L Vue (up to 2007) on the low fan setting. If anyone could pull their fan plug and get voltage at startup with engine running and AC engaged, that would be a big help. I am thinking that should engage the fan at low speed (under 14 volts), with high speed fan (14 volts) engaging with AC on and engine up to operating temp. I suspect that 3.3 volts is too low for the fan to spin at low speed, and the true value should be somewhere between 6 and 8 volts.

Thanks,

Tom Werner

 

Here is a diagnostic video on a 2003 Saturn Vue 2.2L. It looks like he has already replaced some parts, but it does go through low and high speed fan settings, and location of the radiator fan resistor.

Tom

 

Online Saturn Manuals -- The CHARM ProjectEnlightened by
grcauto8453

https://charm.li/Saturn/

 

These online manuals are very informative.

 

I ordered a new radiator fan resistor -- GM GENUINE 25820977 -- available at Rockauto.com and amazon.com for about $38 buck.

The resistance on the old unit was infinite, and the new unit was about 0.7 ohms. The voltage at the radiator fan connection with the new resistor was 14v on both high fan (fan 1) and low fan (fan 2) settings, so the resistor must significantly reduce the amperage going through it.

I would say that a very low voltage reading at the fan connector (I was getting 3.3V on the low fan setting) is a very good indication of a failing or failed radiator fan resistor.

Bottom line, the radiator fan now comes on when the AC is engaged. The result of this fix is cold air blows through the vent at idle.

I can't say how many resistors go bad, and it is only on the 2.2L FWD Vue, not the 6-cyl (I did not check other models, but the fan resistor is likely only used on single fan cooling systems), but mine was totally shot. Access to the resistor is easiest by removing the driver headlight, per the video posted earlier..

I will update if any new info comes to light, but for now the radiator fan is operating properly.

Tom Werner


New Resistor on the Left. Old resistor on the right.


7

 

Awesome.
Glad you were able to track it down.

Also, thank you for coming back and posting the resolution. You're in the minority in that respect. But you've probably helped 25 people in the future so again, thanks.

 

My wife and I use our Vue as a tow vehicle for our RV. It has low miles for its age (82k Miles), and it has a lot of expensive tow equipment. So, it is a vehicle that I want to keep running as long as I can, especially since fewer and fewer new vehicles can be flat towed.

These forums are a great resource for those of us who need to keep our cars running. There was another site I used to visit, Saturnfans.com, that has gone dark, and with it all the collective knowledge that was shared is kaput. That is a big loss.

Fortunately, I found this site. And, you are correct: There are lots of posts with problems, and few that follow through with the eventual solution. Hopefully the next guy with a similar problem can resolve it in about a half hour of diagnostics vs what seemed like days for me. And, I hope to benefit from someone else's diligence the next time I am in a pickle.

Thanks to those who keep this site up and running, and especially those who contribute to our collective wisdom!

Tom