Tlwev

Ok guys here we go again. Followed all advice and performed WSM as much as my limited knowledge would allow. all was well in the fan and cooling dept until two days ago when the drivers side fan decided to stop working Pass side fan working fine. Went thru all the simple tests like key on ,AC and blower on and only the pass side fan worked. Unplugged rad temp switch turned on key and no fan.Chased down voltages. Good from battery to CE box, jumping pins 4 and 8 in forward controller and the fan came on. Applied direct voltage to drivers side fan and it worked good. Plugged fan back in and no go. I have found that my fog lights aren’t working. Found a melted fuse , replaced fuse, checked contact, used D100 and still no fog lights or fan. As far as I can tell I’m getting power to the fan through all channels except the cable that actually plugs into the fan motor. AC, blower and such work fine. Followed procedure for rad temp switch test, unplugged it turned on ignition and no fans. Sorry that is a bit disjointed and out of sequence. I switched horn relay and relay IV fog lights as suggested but no fan. I read that the X bus relay influences the fan but my Ac and blower are working fine. Again this probably sounds disjointed and that is my modus operrendi so that could be a big issue. Any suggestions appreciated

Mrmerlin

Drop the CE panel and put D100 on the rear side fuse contacts for the fans
heck do everything on the back..
NOTE if you see any indications of water intrusion,
IE corrosion then the chances are good the contacts are corroded.
Then this will segway to dropping the blower box to reseal it with new 3M sticky putty

Tlwev

Thanks M. That is about the only thing I haven’t tried. Have a new relay coming from Roger hopefully this and the relay will get things set straight

928Collector

This auxiliary air cooling fan turns when I put an 8v battery to the terminals but doesn't turn when the car is running/hot.

Can anyone one help with some specifics as there is some mention of supplemental fuses/relays in the engine bay?
Or what is the fuse/relay number in the fuse box for this auxiliary cooling fan? I couldn't find it on the fuse charts for a 1980 on 928sRus.
To the advice of someone above I put an 8V battery to the terminal nodes and the fan turned slowly - but they definitely turned. Does that tell me its not the fan motor itself?
Also, the lager/metal radiator fan turns well - but will I run the risk of the car overheating or is this just an auxiliary fan that my highway driving is sufficiently cooling the front of the radiator down with?
Any advice/help much appreciated.