dougs968

Hi guys, I was going to drive the 968 yesterday, but the battery was totally dead. Figured I left something on so I put it on the charger and took the bike instead. This morning all is good so I drove it to work. Made one stop on the way and noticed that the fan/fans were running after the engine was shut off. Unusual in this cool weather and light traffic. Whatever, did my business and back in ten minutes and the fans were off. Drove two miles to work and the fans are on again. I go in and come back out a couple minutes later...still on. Now I'm really curious. Pop the hood and see that both radiator fan motors are running. I pull the fan relay and they stop, of course. Went out an hour later plugged the relay back in and both fans come back on.

Any ideas? My first thought is a bad relay, it sounds a little rattly on the inside. It was a little warm to the touch when I removed it the first time too.

Thanks

tamathumper

That, or a dying thermofan switch.

Paul Waterloo

I would say the fan switch....easy enough to test. Obviously the relay works, and you almost never hear of a "stuck" relay, only one that fails due to the contacts going bad or the coil open circuiting. Normal failure mode of a relay is deenergized

MB968

Paul's logic sounds good. I'd also start with the fan switch, unless you have a relay to swap since that would be easy to rule out. Is there another relay in the fuse area that is identical?? Don't know enough about that area to know.

dougs968

Thanks guys! I'll check out the fan switch, not sure where its located though. Probably run up the road and get one in a bit. I will report back when I'm convinced its fixed.

Paul Waterloo

I don't know where the sensor is either....but it would make sense it's on the engine vs. the radiator....my guess is near the intake manifold.

It has three wires, all 1.5 mm (regular looking wires, not HUGE, not TINY), one is red/white stripe, one is brown and another is brown/yellow stripe.

The brown is the ground, it goes to ground connection 36.

jeff968

I assume all looks good as per the temperature gauge? It is not that they SHOULD be on?

dougs968

Coolant level is good. Temperature gauge in normal operating range. I'm gonna plug the relay back in and blast up to Oklahoma Foreign now. Be back in a little while.

dougs968

Paul thanks for posting the schematic. It may come in handy.

dougs968

Ok, it appears that the switch is on the radiator drivers side, upper corner under a coolant hose. OK Foreign out of new stock. Was told it was a pretty available through the regular parts stores. Also switch is in common with a VW one too, I'm told.

BTW, when I pluged the relay in after sitting for 6 hours the fans came on. Relay didn't smell burned either.

Off to NAPA.

Paul Waterloo

If you have a multi meter, put it on resistance, and measure the resistance between 1 and 3 and 2 and 3. This would tell you if the 92 C switch is closed (2 and 3) or 102 C switch (1 and 3) is closed....that way you can verify it failed.

Less than 1 ohm, it's closed, greater than 1,000 ohms (should read MUCH higher than that) it's open.

Paul Waterloo

And I see Clark's Garage already has almost all of this:

http://www.clarks-garage.com/shop-manual/cool-01.htm

dougs968

Thanks very much Paul and Tamathumper, it sure is pointing to the switch. Ordered a new switch from the local NAPA, be in tomorrow. I have a Fluke 23 series II multimeter to check the old and new switches. I am very unhandy around electrical stuff unlike most of you guys. I appreciate the guidance and the Clark's Garage link.

tamathumper

You're welcome. Which temperature range did you order? Any range will function, but ideally it should be a match for the thermostat.

dougs968

That I do not know. The switch I ordered did have a 951 prefix though.