little fan wiring question 2001 xc70

Post by **darrylrobert** » 21 Jun 2020, 07:32

I am going to install the little fan 6/44 onto my ecm box. Would it work if i connected to the ecm as per thus wiring diagram, or would the ecm need programming?

Should i just connect itindependently with a thermostat?

: Ecm fan; Screenshot_2020-06-21-23-21-45.png (67.83 KiB) Viewed 559 times

Post by **SuperHerman** » 21 Jun 2020, 12:20

Do you have a picture of the actual physical fans (original and new).

Looking at the wire diagram it appears to be a standard brushed fan as it has only two wires feeding it, unless 6/44 is some kind of connector. If two wires I don't see how it would take programming - on/off input would be from elsewhere as well as voltage control (if it has it) to vary the fan speed.

A few pictures would help.

Post by **jonesg** » 21 Jun 2020, 17:16

looks like this. Draws cool air from small air duct to passenger cabin.

https://www.ebay.com/itm/VOLVO-S80-S60- ... 2785621226

Post by **darrylrobert** » 21 Jun 2020, 21:19

As per the wiring diagram the fan has a pos+input and -neg input .It has two functions, fan on ...fan off. This can still be controlled by the ECM via a ground input. My question is does the ECM need to be programmed using VIDA or is it "plug and play"?

Post by **jonesg** » 21 Jun 2020, 23:57

... there is no downside to having the fan always run when ignition is on.
I'll go out later and check mine, I have an extra ecm fan from the junkyard.

Post by **jonesg** » 22 Jun 2020, 19:32

jonesg wrote: ↑21 Jun 2020, 23:57 ... there is no downside to having the fan always run when ignition is on.
I'll go out later and check mine, I have an extra ecm fan from the junkyard.

oops, forgot to test mine before it went dark.
Tues for sure.

Post by **SuperHerman** » 22 Jun 2020, 21:14

I doubt that their is software on the fan assembly. You can look up the part and dig around to see if there is a software download associated with it.

Again, look at the fan - if there are only two wires and you can power it on and off with external voltage it is a straight brushed fan. Speed control, if any would be via the associated computer, which is separate and upstream.

I don't see the wire diagram showing a ground point, which it should if the fan has one. The housing is also plastic so grounding is problematic. My take is it is just a fan in a fancy plastic enclosure. No software.

Post by **jonesg** » 23 Jun 2020, 07:29

SuperHerman wrote: ↑22 Jun 2020, 21:14 I doubt that their is software on the fan assembly. You can look up the part and dig around to see if there is a software download associated with it.

Again, look at the fan - if there are only two wires and you can power it on and off with external voltage it is a straight brushed fan. Speed control, if any would be via the associated computer, which is separate and upstream.

I don't see the wire diagram showing a ground point, which it should if the fan has one. The housing is also plastic so grounding is problematic. My take is it is just a fan in a fancy plastic enclosure. No software.

Its 2 two wires only.
doesn't turn on with ignition on, ecm ground switched.
My timing belt is off so I couldn't test engine on.
The 2 prong socket connector is be located behind the box, clipped to the inner fender.
Fuse #8 , also controls acc pedal sensor and AC.

Post by **SuperHerman** » 23 Jun 2020, 12:36

I am a bit confused. Are you retrofitting or repairing/replacing?

My original reading of your request was that you were replacing an existing fan.

If a retrofit then it may require the ECM to have that instruction and it may require some trigger sensor which tells the ECM it is getting warm. I have no way of knowing, but I do recall there is a dangling harness with no mate floating around unused, at least in a few of my prior Volvos.

Assuming you have a dangling harness and it is a mate, plug the fan in. Take a hair dryer, and with some intelligence, while the car is parked and running, add heat to the ECM. Again with some intelligence as all you want to do is get the ECM warm where it would want to turn on the cooling fan. That will give you your answer.

The fan in the photos is a typical brushed motor - speed would be controlled by changing voltage, if the motor is not run at a single speed by the ECM it may always be on by design. Only way to figure this out is to see if someone with the fan installed can verify operation. I have seen posts where people just swap out the motor as a repair for failed units (not sure which brand of car though).

If you are retrofitting a fan for additional cooling, and your car does not have a fan harness already installed, you can just hard wire it and let it run all the time. But I do have one concern, if the ECM is handling the voltage, it may not be 12Vs, it could be 6Vs. There should be a part number or specs on the motor telling you what the voltage range for the motor. Other way to tell is have someone with a fan read the voltage the fan is getting when operational.