Re: UrQ low-temp idiot light sensor

[GADBOISMT@aol.com]

In a message dated 96-09-01 15:22:26 EDT, you write:

<< ubj:	Re: UrQ low-temp idiot light sensor
 Date:	96-09-01 15:22:26 EDT
 From:	rdh@UrQ.East.Sun.COM (Robert Houk - SMCC Bos Desktop Hardware)
 Sender:	owner-quattro@coimbra.ans.net
 Reply-to:	rdh@UrQ.East.Sun.COM
 To:	
    > Unfortunately, now the idiot light
    > starts dim and brightens as the engine warms up.
 
    > The part number called out is a two-pin affair, with one pin being a
neg
    > coef thermistor relative to ground (about 4.5K at 10F, dropping to
around
    > 70 Ohms at 212F), and the other being a straight thermo-switch that
seems
    > to open around 240-250F (matching the "120 C" stamped on the body).
 
    Sounds like the pins are switched.
 
 Nah, 'cuz the switch doesn't "switch" till 120C, which is overheat
territory,
 so I assume that's the standard Coupe/I5 overtemp alarm switch -- as opposed
 to the UrQ, which has a different overtemp switch sandwiched into the
coolant
 tank return line . . . wierd, but somehow typically Audi: why bother to use
 an already-present sensor/switch mounted in the head, when you could add yet
 another [blankety-blank] switch on the other side of the engine bay comple-
 tely divorced from the head/block [where the temperature is IMPORTANT], not
 to mention the extra wiring, crimp connectors, etc., and so forth!
 
 					-RDH
 
  >>

Unfortunately there are way too MANY temperature sensors in the UrQ engine.
 Two basic temperature switches are 1) for the overheat >125 degree C. near
the front of the cylinder head (current track 144), [that's your on/off
switch] and 2) the cold engine sensor in the back of the engine (current
track 29) [that's your variable resistor i.e. the blue light].  There's
probably more but I don't care any more. 

Mark.