2002 XC70 engine fan relay .... where is it

[L Stewart]

OK, I am at a party in the backwoods of North Carolina. All is well, we park the car, get out and I notice the fan is still running. I think no prob, it's done that before, it'll cut off in a few minutes ..... flash forward 5 hours, a few beers, and NO LIGHT what so ever later ..... we return to find the car DEAD! but with the slight sound of a dying fan still trying to turn SUCKING the remaining few volts/Amps outta my battery. Well after several foul words and using the flashlight App with my phone I finally get the car jumped and running. I looked for the fuse/relay to pull to shut off the fan to no avail. I finally unplugged it and dug back into it today. I still can't find the dammed thing! I put a volt meter on the plug and proceeded to unplug every fuse and relay in the fuse panel in the engine compartment, left of the Dash, and even took out the one on the rear panel of the car and pulled MOST of those. SO ..... Any and all help, advise, knowledge will be appreciated!

Thanks .... I'm going to bed now. (3rd shifter)

Larry S

[jda2000]

check for codes.

Usually the problem is a failed coolant temp sensor, that keeps the fan going.

[L Stewart]

No codes showed up. The message center didn't have anything, the yellow and red lights didn't show up, the analog temp gauge didn't show anything out of the ordinary, and I have a scangauge hooked up to the OBD port and it shows normal temps and no codes.

Thanks for the info. Would the coolant sensor still deliver normal temps?

[Willy]

There is no fan relay, it is controlled by a power transistor, see pdf. These transistors sometimes fail, often in a short circuit, thus always
allowing current to the fan. This explains what happend to your car. The fan control unit (4/71) is attached to the housing of the fan.
Willy

[L Stewart]

OK, found out from a repair shop where it's at. It's attached to the fan itself. Replacing it INCLUDES replacing the fan at a cost of >$500.Hmmm ... now for other options. considering finding one in a junkyard and just getting the relay from it or getting an aftermarket fan for it. Any suggestions there?
Wish me luck. this car is getting to be a money pit!!
I didn't see Willy's post until after posting this.

[Willy]

I haven't tried this, but if it turns out that the control unit is the problem, it may be worth the trouble trying
to open it, replacing a transistor (or having it replaced) will be much cheaper.
Willy

[barbershores]

I have the same problem on my 2002 xc70 with 188,000 miles. I found a new after market replacement online for about $200. But, I don't want to go through that work and expense to find it fails after a couple of months. Instead, I intend to mouse it. Fortunately, when the unit fails, it fails in the "on" position. So, I purchased an adjustable temperature switch. I had to go to the post office to sign for it to pick it up. It actually came from China. $8.99 including shipping. Not sure if this is where I got it from, but this is the part: http://www.dx.com/p/w1701-temperatur...3#.U9FZZ7H68lE

I intend to tape it with insulation over the top to the top of the radiator hose on the far left facing the engine, right close to the radiator. This is the hose that runs from the radiator to the thermostat. I will cut the red wire, +12vcd, between the cable connector and the fan control on the fan. Just switch between them. I am now looking for the best place to connect up the 12vdc to operate the switch.

Best of luck,

Barbershores

[damian1108]

I had the same problem, the radiator fan did not turn off ever, 2002 v70 xc (237,000), I replaced it with a fan control switch which I pull from the u-pull salvage for $22.00. I solved the problem.
Now I have a code for a bad oxygen sensor, which I am planning to clean up.
Damian

[nickbw]

No tried that it is darned hard to open because it is so well protected from the weather but that pdf is just a schematic, the real thing is very complex and you will need to be an electronics expert and a wizard at soldering smd components. I know someone who repairs and upgrades Apple Time Capsules (they have capacitors which fail in a similar way causing shorts which also blow the transistors) and even he would turn this job down. I got a complete fan/fan shroud and controller for £25 from a brakers - they are all the same for the given year on V70/XC. Two 10mm bolts, two electrical connectors to the harness, ten to fifteen minutes tops.

https://app.box.com/s/gm2aanfiiz1c7eqx39pf
https://app.box.com/s/20j8f7j5pxpd2sn1va8y
https://app.box.com/s/kpy7kq5dpn0ukva4q3r0
https://app.box.com/s/c86cmpsamexbne0o12ky
https://app.box.com/s/z65y4zdpnlkq9czxxapy
https://app.box.com/s/zgt0absm9b8ovl52jyks

[Willy]

I had the same problem, the radiator fan did not turn off ever, 2002 v70 xc (237,000), I replaced it with a fan control switch which I pull from the u-pull salvage for $22.00. I solved the problem.
Now I have a code for a bad oxygen sensor, which I am planning to clean up.
Damian

I also had an oxygen sensor failure. The error code meant that the signal was out of range.
The problem turned to be the wiring, not the sensor itself. It was the sensor near the heat-shield
that's mounted on the exhaust collector. One of the wires was broken where the wiring was strapped to
tight (between the engine and the firewall. I found it by cutting through the heat-insulation of the wires
and then pulling the wires one by one. If a wire stretches, it is broken inside.
The repair seems easy but the wires are not simply solderable, it's a kind of steel. Silver-soldering works.
Willy