V70 cooling fan p/n 30749759

Duncx · Post by **Duncx** » 30 May 2022, 14:50

The radiator cooling fan on my 2005 V70 2.5T has decided to die now that the weather is getting hot.

I have tried 2 from scrapyard as well as the original and neither will run when triggerd with VIDA/DICE.

The new price is somewhat silly at around $500US with lots of Google searching.

Anybody have any leads on where to find one at a decent price as I can't afford to put $500US into such an old car?

Cheers, Duncan

jking4020 · Post by **jking4020** » 30 May 2022, 15:23

I've replaced my the 01 70XC cooling fan with a junkyard S60 cooling fan of the same year and it worked great. Usually when the fan modulator goes bad they stay on full blast even when you turn off the car. If you can't get yours to work at all it could be a ECM problem. Good fortune to you.

jking4020 · Post by **jking4020** » 30 May 2022, 15:25

Have you traced all the wires to make sure there are no corroded or cut parts? And of course the fuses.

Post by **jonesg** » 30 May 2022, 16:10

Just solved this same issue yesterday.
Its likely not the fan.
Vida should show relay signal missing if you do a new scan.

Its probably the purple wire.
Look for 2.8v where the loom enters the junction/fuse box, probe the plug whilst commanding fan on.
If yes, test at the fan plug.
Its losing the signal somewhere.
I cut the signal wire where is exits the ECM box and put a buzzer continuity tester on it , then i traced the buzzer signal,
disconnect battery first.
Found the problem near the fan plug, gremlins inside the insulation.
Fixed the bad section and resoldered the signal wire, heatshrink and elec liquid tape.

Post by **jonesg** » 30 May 2022, 17:17

I just took a quick video showing how I tracked mine down.
Disconnect battery if you resort to my method,
I think a decent meter should be able to track the 2.8v signal though.

Post by **jonesg** » 30 May 2022, 18:27

Harbor freight sells a version of fox and hound cable tracker for $26 that some guys really like.
If there was a store closer I'd buy one.

Duncx · Post by **Duncx** » 31 May 2022, 07:51

I checked last night and there is a disconnect in the purple/mauve lead running from the fusebox to the fan.

I cut it inside the fusebox and by the fan plug and ran a jumper ..... I see 11.03V (battery voltage as battery not the best) no matter what fan speed I command.

I plugged in the fan and nothing from any speed.

I am confused .... why do you guys see 2.8V and why do I see 11.03V and why does my fan do nothing?

Thanks for all and any help, Duncan

Post by **br0dy519** » 31 May 2022, 10:24

jonesg wrote: ↑30 May 2022, 18:27 Harbor freight sells a version of fox and hound cable tracker for $26 that some guys really like.
If there was a store closer I'd buy one.

Dang I was at HF on Saturday I wish I saw this video! That tool is worth it's weight in gold!!

Post by **jonesg** » 31 May 2022, 11:02

Duncx wrote: ↑31 May 2022, 07:51 I checked last night and there is a disconnect in the purple/mauve lead running from the fusebox to the fan.

I cut it inside the fusebox and by the fan plug and ran a jumper ..... I see 11.03V (battery voltage as battery not the best) no matter what fan speed I command.

I plugged in the fan and nothing from any speed.

I am confused .... why do you guys see 2.8V and why do I see 11.03V and why does my fan do nothing?

Thanks for all and any help, Duncan

Purple wire is 2.8v when commanded on. I think the speed is controlled by the pulse width, not voltage.
Fan sees constant 12v on the red cable.
With fan commanded on in Vida you should get 2.8 between purple and ground.

It's confusing, that's why I snipped the purple wire near the ecm box and put my continuity tester on it there.

Duncx · Post by **Duncx** » 01 Jun 2022, 16:41

I don't know what is happening and why I am seeing such a high voltage.

2.8V is usually one of the choices for a digital signal, a common other being 5V. The fact that it is 2.8V irrespective of fan speed setting just goes to make me believe that to be the case even more.

The fact that, in my case, there is 11V on the violet wire I see as being an issue. It could, at worst, potentially blow the electronics in the fan module or, at best, it just won't be recognised as a signal.

It is the CEM sending the 11V which makes me think I may have a CEM issue.

I have decided to go old school and put a couple of manual fans in place of the standard setup. I'll run them off a switch while I work out a temperature switch solution.

That at least gives me a car I can drive even if it is bodged together ..... it's a very old car that I use as my work vehicle.

Putting in another fan, scrapyard or otherwise, just runs the risk of blowing that fan and a replacement CEM is out of the budget.

I do love these Volvos, amazing work horses as well as passenger vehicles, but damn they can make them far more complicated than they need to be.