No heat in '91 CQ

[Tony Lum]

At 11:46 PM 12/21/2004 -0500, Jeff Pereira wrote:
>I am not getting any heat in my '91 CQ with electronic climate control.
>
>Everything else seems to be working fine, but I am just not getting
>any warm air to come out.
>
>Any suggestions??
>
>jeff
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Hi Jeff,

I'm having a little problem like that in my Mom's '89 100 Avant.  First 
check to see that the heater valve is open with the heat on.  I'm not sure 
about the CQ, but on T44 cars (5K, 1C, 2C) the heater valve is vacuum 
controlled.  The arm on the valve should NOT be pulled toward the vacuum 
servo when the heater is on.  Now with the heater valve open, hot coolant 
from the head will circulate through the heater core.

The problem with no heat is that the temperature flap, which is controlled 
by a servo motor, gets stuck in the cold position.  You can tell that by 
turning on the diagnostic mode of the CC head.  Pressing the inside/outside 
temp button along with the off button will put you in diag mode.  Channel 
'01 displays any faults in the system.  In my case I'm getting a "15" code 
which says the temp flap position is not matching the programmed 
output.  You can see the actual flap position of the servo motor on channel 
8, while channel 9 stores the programmed position.  They're supposed to 
track each other within 3 units, otherwise calibration is necessary.  Use 
the up and down temp control buttons to change channels and the in/out 
button to display the channel reading.  BTW, channel 11 is a built in 
voltmeter which you can use to get a rough estimate of the system voltage.

The flap control servo motor is erratic, working sometimes, and sometimes 
it slams to full cold and just stays there.  I took the servo motor apart 
and the whole thing is run by a little toy like motor.  I'm going to try to 
clean the motor using R/C motor spray and "comm" drops the way you'd clean 
a R/C car's motor.

HTH,


--
Tony

'80 5KS
83 urquattro #900302
'85 4kq
'87 5kcstq
'87.5 coupe GT