johnfm

Strange heater problem - but its 1 degree outside, so I haven't searched the archives!!

The interior fan only works with temp setting on the blue dot. As soon as I set the temp on the dial, the fan cuts out???

I note that when I just turn ignition key (without starting engine), the rear blower in engine bay doesn't operate.

Is there a fuse for the rear fan in engine bay??

I am not at my usual PC (with workshop manual on PC), hence the stupid questions!!

Andy Roe

Most likely that your rear blower fuse has blown, sometimes caused by a worn out rear blower bearing. Check the rear fuse box next to the distributors.

Andy

johnfm

Problem solved - it was fuse in rear fuse box. The suspension installers had not put the 'coil fuse thingy' back into the heater pipe work. This must have casued the fuse to blow.

Fred, Long Island

Fuse should be a 30 amp per service bulletin. The original 25 would fail.

Adrian

Dear John,
The coil thingy is actually the blower resistor. Without this installed the fan will not run. It will not cause the fuse to blow. What would cause the fuse to blow is the contact for the blower resistor carrying 12VDC touching something metal around where it was left hanging. The rear blower circuit is critical to the operation of all functions of this system. When it does not work nothing else works properly.
Ciao,
Adrian
911C4

johnfm

Adrian

it was just left dangling, so it probably did ground somewhere. I fitted it back into its slot & replaced the burnt 30 A fuse.

Everything peachy!