PorKen

Found this mystery blue/green wire today, with a protected male spade connector.

It turns out it's where you connect the wire harness for the auto trans cooler overheat switch if you have a factory towbar. (The switch screws in where the plug is on the cooler.)

It's wired parallel with the radiator temp switch, and the freon heat switch. The wire goes to ground when any of the switches trigger, activating the CE fan relay. (It's not part of the hot intake reduced speed circuit.)

It would be an easy way to turn on a relay for aftermarket fan(s)?

PorKen

IE. plug a non-insulated male spade into the connector, connected to the (-) of the new fan relay. When the A/C or radiator sensor are triggered, the relay will close.

You can find the oil temperature switch and circuit on the 85 and 86 WSM wiring pages for 'Ventilation and Heating', 97-H-32.

Part numbers
oil temp switch - 928 606 309 01 ($150)
oil temp switch harness - 928 612 203 00 ($25)

SMTCapeCod

Bumping due to proliferation of fan install threads recently...

928NOOBIE

oops..I was supposed to post pics of a couple places for grounds wasn't I...let me do that real quick...sorry SMT...I'm tragically lazy.

928NOOBIE

Ground Point just in front of the passenger side Ignition Coil (S3)





Hot lead for fans on hot point (fit just fine)





Pull back on main fan power to show jacketed wire.





Fits nice behind the cover no problemo.


I could not get a picture of the other ground I cleaned..but on the driver's side coil attachment there is a ground from the engine. As I've mentioned I used the driver's side coil + lead for my switched 12 V signal ( I fought the fan lead and wound up just blowing the fuse on my windshield wipers - don't ask).

Also, I have the new 928 Int'l radiator, an awesome unit but the fins are very thin and I was having trouble with the sensor probe remaining snug in there. I wound up after punching about 5 holes in there using some blue threadlocker to keep it from falling out (it literally did that...the fins aren't thick enough to remain in place..they are more like the ones in the condenser coil or even more fragile...wonderfully efficient at their job..but not so efficient at holding things....so far the blue threadlocker is working like a charm.

SMTCapeCod

Thank you!
The tip on the wiper circuit may have saved me some headaches. Working along the same lines as a known-good install should help reduce my Murphy factor.
I would like to do the radiator at the same time, ANd the new harness 928 INtl just rolled out...but it's just not feasible at present/on a precautionary basis.
One Q- "jacketed wire", are you talking about the split/corrugated sleeve, or is the bonded wire insulation different/more robust than your typical stock
Okay two- did you use inline fuse protection for trigger or power feed?

SMTCapeCod

OK, I was thinking of using the wire in post #1 for remote turn on signal but after another read through I see that it would provide a temp signal, in lieu of the one provided by the kit?
Edit: on re-read, I guess not, it triggers the factory fan relay which is often supplanted during aftermarket an/controller install.

But then, according to this thread, at least the freon temp trigger would be lost:
https://rennlist.com/forums/928-foru...questions.html
That seems suboptimal.

So, any reason to select the driver's instead of passenger side coil for the turn on signal?
And, where in the radiator did you place the probe? I have to refresh my memory on the fundamental aspect of coolant flow.

Must be a somewhat elegant solution to use the factory sensor array to activate the aftermarket fans??

Seems like the Sharkblade did a bit of a hybrid approach, using both temp and factory triggers.
https://rennlist.com/forums/928-foru...an-system.html
Is the concern with using the factory fan triggers, the capacity of the oroignal wire/relay system to handle the amp draw?