Radiator Fan Speed, When it Should Run

Post by **bmdubya1198** » 22 Mar 2018, 17:41

A post in my last thread got me thinking about if my fan is not running in its low speed. I have been doing extensive troubleshooting over the past couple weeks on my car's "hiccup," and I've pretty much got it down to the cam sensor connector being rather disintegrated. Could also be the MAF or voltage regulator, but I'll leave that for another thread if I can't figure it out. I'm just relieved all of my wiring has tested good. However, my fan jumping immediately to high speed might still be causing this drop in RPM.
When I turn on my A/C, the fan doesn't kick on. IIRC, it's supposed to, whether the engine is hot or not. I tried it on my cousin's 1999 S70, and his fan didn't kick on either, but at the time both cars were cold. Maybe that was the issue, but I wanted to confirm that.

Otherwise, when is the fan supposed to be running at its high or low speeds? The only time I notice the fan running is when I get home and I let it idle for a couple seconds, and it is always on what I assume is the high speed. I have never noticed it running on the low speed.

How do I know the fan is functioning correctly? What I wanted to accomplish with this thread is a "list" of when the fan is supposed to be on low and when it's supposed to be on high for troubleshooting purposes. This seems like it should be straightforward, but I haven't found anything online about this.
Maybe I just need to replace the fan relay... who knows. I replaced it with a junkyard relay after buying my car since it never had one to begin with (it was wrecked). ECT tested good and the thermostat is only a year and a half old. My temp gauge reads normal, so no concerns about the fan not cooling sufficiently.

Post by **bmdubya1198** » 23 Mar 2018, 14:21

Checked if my fan came on with my A/C today while the engine was at operating temperature, and it did not. The compressor kicks right on and my A/C was cold, but the fan didn't turn on.
It came on a minute or so later on high speed, but that was because of the engine temperature, I think.

Post by **FlyingVolvo** » 23 Mar 2018, 14:45

bmdubya1198 wrote: ↑23 Mar 2018, 14:21 Checked if my fan came on with my A/C today while the engine was at operating temperature, and it did not. The compressor kicks right on and my A/C was cold, but the fan didn't turn on.
It came on a minute or so later on high speed, but that was because of the engine temperature, I think.

I had a similar issue with the fan not working with the AC on (as it should). Replaced the fan relay and all was well. Hope your solution is that simple!

Post by **bmdubya1198** » 23 Mar 2018, 17:11

That is reassuring. I’ll have to grab one next time I’m at the junkyard. Unfortunately it’s supposed to be raining all weekend.

Post by **esl_97_850_T5** » 23 Mar 2018, 18:30

A '98 V70 GLT presumably has a Motronic 4.4 ECM.

volvo850diag v0.8 can issue M44 test commands to:

- run fan on high, or
- run fan on low.

A summary of how to use volvo850diag to test the '98 V70 GLT fan speeds:

- Download latest volvo850diag.zip.
- Unzip with WinZip, 7-Zip, etc (not with Windows Explorer).
- Get it setup (using instructions in its readme and in the "local" volvo850diag.html extracted from the .zip).
- Run the "local" volvo850diag.html with IE.
- Click "Options", then change "scanner_type", if necessary, then click "Save" (if option was changed).
- Click "Start Realterm" to get your ELM327 device connected to your car.
- Click "Read All DTCs" and let it run to completion.
- The ECU 7A Setup button should now be one of the enabled buttons.
- Click ECU 7A "Read DTCs" (and wait a few seconds).
- Underneath volvo850diag's line of ECU 7A buttons, there is a pulldown labelled
"Select item for M44 to test/control" (or something similar). It should now be enabled.
- Select either one of these from that "Select item for M44 to test/control" pulldown:
* Engine Coolant Fan, High (full speed)
* Engine Coolant Fan, Low (half speed)
- Click Test.
- Listen to the fan speed as the fan cycles on and off 3 times.
- Select the alternate fan speed, click Test, then listen to its different fan speed as it cycles on/off.

That's one way to see/hear the different fan speeds on '96-'98 850/S70/V70/C70/XC70.

Post by **bmdubya1198** » 23 Mar 2018, 18:38

esl_97_850_T5 wrote: ↑23 Mar 2018, 18:30 A '98 V70 GLT presumably has a Motronic 4.4 ECM.

volvo850diag v0.8 can issue M44 test commands to:

- run fan on high, or
- run fan on low.

A summary of how to use volvo850diag to test the '98 V70 GLT fan speeds:

- Download latest volvo850diag.zip.
- Unzip with WinZip, 7-Zip, etc (not with Windows Explorer).
- Get it setup (using instructions in its readme and in the "local" volvo850diag.html extracted from the .zip).
- Run the "local" volvo850diag.html with IE.
- Click "Options", then change "scanner_type", if necessary, then click "Save" (if option was changed).
- Click "Start Realterm" to get your ELM327 device connected to your car.
- Click "Read All DTCs" and let it run to completion.
- The ECU 7A Setup button should now be one of the enabled buttons.
- Click ECU 7A "Read DTCs" (and wait a few seconds).
- Underneath volvo850diag's line of ECU 7A buttons, there is a pulldown labelled
"Select item for M44 to test/control" (or something similar). It should now be enabled.
- Select either one of these from that "Select item for M44 to test/control" pulldown:
* Engine Coolant Fan, High (full speed)
* Engine Coolant Fan, Low (half speed)
- Click Test.
- Listen to the fan speed as the fan cycles on and off 3 times.
- Select the alternate fan speed, click Test, then listen to its different fan speed as it cycles on/off.

That's one way to see/hear the different fan speeds on '96-'98 850/S70/V70/C70/XC70.

I figured there had to be some type of way to activate it manually. I'll give that a try this weekend if I can get my bluetooth ELM327 adapter set up right. Thanks for posting this!

BlackThunder · Post by **BlackThunder** » 28 Mar 2018, 09:46

esl_97_850_T5 wrote: ↑23 Mar 2018, 18:30 A '98 V70 GLT presumably has a Motronic 4.4 ECM.

volvo850diag v0.8 can issue M44 test commands to:

- run fan on high, or
- run fan on low.

A summary of how to use volvo850diag to test the '98 V70 GLT fan speeds:

- Download latest volvo850diag.zip.
- Unzip with WinZip, 7-Zip, etc (not with Windows Explorer).
- Get it setup (using instructions in its readme and in the "local" volvo850diag.html extracted from the .zip).
- Run the "local" volvo850diag.html with IE.
- Click "Options", then change "scanner_type", if necessary, then click "Save" (if option was changed).
- Click "Start Realterm" to get your ELM327 device connected to your car.
- Click "Read All DTCs" and let it run to completion.
- The ECU 7A Setup button should now be one of the enabled buttons.
- Click ECU 7A "Read DTCs" (and wait a few seconds).
- Underneath volvo850diag's line of ECU 7A buttons, there is a pulldown labelled
"Select item for M44 to test/control" (or something similar). It should now be enabled.
- Select either one of these from that "Select item for M44 to test/control" pulldown:
* Engine Coolant Fan, High (full speed)
* Engine Coolant Fan, Low (half speed)
- Click Test.
- Listen to the fan speed as the fan cycles on and off 3 times.
- Select the alternate fan speed, click Test, then listen to its different fan speed as it cycles on/off.

That's one way to see/hear the different fan speeds on '96-'98 850/S70/V70/C70/XC70.

Will this work on 1997 850? I'll have to see if I can get my computer to hook up to my ELM 327 too. Please let me know if someone gets this to work with their Windows or Mac. I have Torque but it can't do this stuff, I don't think. Can it?

Post by **esl_97_850_T5** » 28 Mar 2018, 16:12

Dustin,

1. If your 1997 850 has a Motronic 4.4 ECM (with factory software), then the commands very likely will work (though I have not tested that, since my '97 850 T5 did not have a M44).

If your 1997 850 has a Motronic 4.3 (with factory software), then the commands will definitely *not* work (since there is no ECU 7A).

If your 1997 850 has an M4.4 ECM which has been flashed by someone, thereby overwriting the M4.4 software installed at the factory, then you'll have to ask the question to whoever wrote that updated M4.4 software.

2. I have gotten it to work with WinXP, Win7, and Win10 (for my '98 S70 GLT).

3. I don't think Torque can do this.

BlackThunder · Post by **BlackThunder** » 02 Apr 2018, 08:33

Good info. Thank you.

Dustin

Post by **esl_97_850_T5** » 20 Mar 2019, 14:26

Testing the radiator fan of 96-97 850 / 97-98 S70/V70/C70/XC70 whose ECM is Motronic 4.4 -- by forcing the fan on High or Low for a short time -- can also be performed by xiaotec "850 OBD-II" Android app V1.1.6. Presumably the more recent "850 OBD-II" versions also have the ability to control the radiator fan on 96-98 850/SVC70 with M44.