From: Ian Harvey [ih@ncipher.com]
Sent: Monday, February 14, 2000 5:16 AM
To: 928
Subject: [928] Heater running hot

I've just fixed a problem which caused my climate control to be stuck on
"hot" all the time, however the temperature lever was set. Thanks to all
of you who helped with advice (isn't the Net a great place!). For
reference, here's what happened:

The fault turned out to be in the control loop, rather than the valves
or vacuum system. This consists of the temperature control lever, the
inside temperature sensor in the dash, and the outside temperature
sensor, all wired in series. The connections to the outside temperature
sensor had corroded, leaving the loop open (high resistance); this
corresponds to the "maximum temperature" setting.

The temperature sensor is in front of the left front wheel (i.e.
passenger side on my RHD car). To get at it, the left headlamp needs to
be removed from its carrier:
1. Pop up the headlights
2. Unscrew the 3 Philips screws holding the left-hand side headlamp
cover on & remove it.
3. The bottom of the headlamp is secured to the aiming adjustment cable.
Push the little plastic circlip off the joint, then the ball-end of the
cable will pop out if you pull.
4. Unbolt the two 8mm bolts on either side of the headlamp, detach the
plug, & remove the lamp from the carrier.
5. Pop down the headlights. 

You can then see into the left front wheel well, there's a flexible duct
(taking cooling air to the alternator), and a silver metal sensor
sticking out of it. On my car the leads from this were joined via two
bullet connectors. After cleaning these up, I measured the resistance
across the sensor at 1.2K ohm (at 5-10 deg C outside temperature). I
guess it probably varies between 500-2000 ohms. I then reconnected one
of the leads and joined the other two up via a multimeter switched to
measure current, just to check that nothing else in the loop was broken.
With the engine on & heater controls both at mid-position, this read
(IIRC) 1.2mA. When it was reassembled, the heater was restored to full
operation!


Cheers
IH
80 Euro 928S





From: David Kelly [dkelly@hiwaay.net]
Sent: Monday, January 15, 2001 10:16 PM
To: 928
Subject: [928] Re: fact or myth?

"marcus hutchinson" writes:
> > someone asked this no too long ago, but i never saw a response so.....
> > can you spray WD-40 into the interior temp sensor to quiet a noisy
> > motor?
[...]
> The little motor is sealed, so if the bearings are shot, you have to replace
> it

Missed this the first time around. Subject line doesn't resemble the 
body's contents.

I wouldn't spray WD-40 in the hole. Mostly because of the smell. But as
for the little fan motor unit being expensive (assumed) and sealed I'm
glad I didn't know that when I took mine apart.

The motor is a typical Japanese-like little motor in a can lined with a 
very soft rubber to mute any noises made. Bend a little tab or two and 
you'll have it apart.

Used to be able to purchase "TV Tuner Cleaner" most everywhere. Has a 
unique odor of its own. I have an aerosol can of "Pyroil Brake Parts 
Cleaner" with the same odor. Says its a non-flammable cleaner good for 
all brake parts, electric motors, electric contacts, and CV joints.

I suggest you buy a can of the same or similar.

Take your little fan motor out of its anti-noise can.

Connect its wires to 12V and make it run. Mine was gummed up and had to 
be hand started. Lots of rubber dust.

Clean with above spray until the motor runs freely. Yes, spray it while 
electricity is applied. You did get a non-flammable spray, right?

The stuff is nasty. Stand up wind, outside.

Afterwards, no more than one drop on each end of the motor of the
lightest machine oil you can find. 3-in-1 comes to mind. WD-40 is a
solvent, not a lubricant.

'83 928S

--
David Kelly N4HHE, dkelly@hiwaay.net
=====================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.





From: Wally Plumley [mailto:wplumley@bellsouth.net]
Sent: Saturday, October 19, 2002 9:32 AM
To: 928
Subject: [928] Re: Temp Regulation Problem


At 09:07 AM 10/19/02, 86_5Tiburon wrote:
>The weather is chilly and my HVAC is not regulating cabin temp.
>
>Basically, unless the slider is all the way to the right the temp is cold.
>
>I listened the air mixture motor and only hear the flaps move if the temp
>slider is in the full heat position or off the full heat position.
>Basically full open or closed.


Usually a bad connection in the temp control string, often at the connector 
for the outside temp sensor in the left front fender.

The string is outside temp sensor, inside temp sensor, temp slider, temp 
control motor.

Wally Plumley
928 Specialists
www.928gt.com