928NZ

I have checked everything, and still not getting 12volts at heater fan.
Fan works fine connected direct to 12volts.
Resistor pack is fine - I have two
De icing probe is fine - I have two
Changed both relays and checked and changed fuse.
Outside temp sensor appears OK.
12 volts only reaches climate control area when park lights are switched on.

Any ideas would be appreciated - another hidden fuse?

Landseer

De-ice probes are immaterial to fan op.
What do you mean by "have two"?
(You know that the resistor pack has changed to a new style that requires rewiring, right? Could both be new and never rewired?)
Outside temp sensor is not a factor.
Which two relays and which fuse by number (make sure we are on same page)
Are you knowledgeable about how the sliders on the heat control unit are positioned to get control at fan switch (baseline, again make sure we are thinking alike).

Alan

Does it work in DEF mode - if yes - its likely the blower switch connection in the console.

Else its likely the fuse/blower relay OR the AC head unit connection - if the head unit isn't connected the blower relay does not engage

Alan

928NZ

Thanks for the quick replies.

The "have two" = I have two 928's and have tried the different parts on each car. I have tested both resistor packs with a meter and they have no breaks.

Fan does not work on any setting 1 - 4. I have also tried both A/C head units and pulled them both apart but they both seem fine. 12 volts simply does not reach the head unit on any setting or any slide position. Only lights up when lights are on but that is a different source of 12 volts.

Relays are apparently XX1 and XX11 and I have replaced these from my other car also. Fuse 17 on my car was OK as were all other fuses on the panel.

I thought I had read that the de icing tube needed 12 volts at both sides or the fan would not run.

Landseer

Do you have 12 volts at the appropriate empty relay positions at the panel?
Could be a melt behind panel or wire terminal problem, or melt in the harness(es) on both cars.
Get a good look at plug J wires, for instance. I've had J8 be completely cooked to death on an 84 USA,ie, wires associated with distribution plug J on the front of the panel. This circuit has 25 amp fuses and therefore is carrying some significant power.

Not sure if the resistor check you are doing is appropriate, depends on how you are testing.

928NZ

Thanks again Chris - I will take a look this weekend.
Looked behind the Fuse / Relay panel with an Auto Electrician friend, and he did find one connector that looked burned and he replaced that. Funny I do remember this happening years ago and the fans just started up again for no particular reason.

Landseer

Gotta be a reason on both cars. Probably you just need a couple thinking partners here and some time with a voltmeter.

928NZ

One of my 928s is a road car and the other is a parts car which is Left Hand Drive and cannot be road registered here in New Zealand. I swapped the four piston brakes and suspension - lighter and better seats and interior and recently the newer auto gearbox and LSD.

The parts car is such a handy thing to have when a problem occurs.

Landseer

Ahh, nice avatar! You live in a beautiful country from the pictures and the illustrative map I've seen somewhere.