At 08:44 PM 4/6/00 -0400, Scott Mohr wrote:
>Off the top of their head, does anyone know the resistance values of the outside ac sensor??

You can check the full string (outside, inside, temp slide) by hooking to terminals 4 and 12 on the setting motor on the driver's side of the under-dash system. Should have about 3.7 k ohms w/temp slide at cold end, about 4.7 k w/temp slide on hot end.

Wally Plumley
928 Spcialists


No sensor= hot output unless temp set to 65 degrees
Sensor wires shorted=cold output unless temp set to 85 degrees
Good sensor (Used about $80)= variable vent output which is very comfortable

Outside Sensor Specs:

993 ohms at 0C (32F)
588ohms at 20C (68F)
457ohms at 30C (86F)

However this suggests you still have an open circuit somewhere else...

Test the whole sensor loop: (includes temp control potentiometer)

Between Plug to HVAC Motor Console LHS (HVAC) Plug Pin 4 (YE)*
And Plug to HVAC Motor Console LHS (HVAC) Plug Pin 12 (YE)*

You should see a 1000 ohms variation between 18C - 30C HVAC setting (65F - 86F).



Outside temp sensor part reference:
Conrad Best.-Nr.: 448583

R 25: 470 Ohm
Type: B57164-K472-J
Tolerance: RN 5/10 %
version: K164/470/10%
Operating Temperature: +25 C
Temperature range: -55 up to +125 C

Inside temp sensor part reference:
Conrad Best.-Nr.: 500586

R 25: 2.2 K Ohm
Type: B57164-K222-J
Tolerance: RN 5/10 %
Version: K164/ 2,2K/5%
Operating Temperature: +25 C
Temperature range: -55 up to +125 C

Measure at the mixing flap between both yellow wires. You should see about 3,7 - 4,7kOhm. (control lever cold-warm range)


Ok I found them .
I got the thermistors from
PN 121-102EAJ-Q01
Resistance 1Kohm
Thermistor tolerance 120%
Power rating 1mW/0 degree Centigrade
Resistance ratio 7.04
These are glass enclosed parts similar to what's in the system now for the outside sensor.
They have 2 inch leads.
So with some potting compound ,(JB weld will work) drill out the sensor it has glass in it so be careful,
solder the wires onto the new part then insert into the sensor housing then fill with the potting compound try to put the harness wires into the tube so the new part wont get damaged ,
and pot the harness wires as well
The Newark link was not working for me so I researched several thermistors that approximate the factory sensor specs. The one I purchased from digikey and tested is listed as an NTC 470 ohm, 5% thermistor. That means Negative Temperature Coefficient (i.e., lower resistance at higher temps), 470 ohm at 25C, 5% error. There are others, but I liked the one with this small encapsulated bead and long leads. I soldered the thermistor to leads to the harness connector, potted it with polyurethane, encapsulated it in shrink tubing and placed in the alternator duct. Sensor cost was under $2.