Re: "Outside Temp" adjustable?

[Gerard <gerard@poboxes.com>]

> The temp sensor output to channel 5 (the outside temp sensor that is in
> front of AC condenser) is faulty. It is giving a reading ("142") that says
> it thinks it's about 5 Celsius. This faulty reading, IMO, will keep your AC
> compressor from coming on. Replace it (the sensor).
> 
> The channel 4 reading seems too high, but considering the test conditions,
> it may be OK. It won't affect your AC.

Ok, I removed the black covering. Found the evaporator unit. Saw a
few wires and connectors, matched the connector to the one that is
on the grill and disconnected it. The AC head unit now reports an
error 03, which is correct since the evaporator unit temp sensor is
disconnected. Then tried running the aircon for a while, but still
manage to get warm air through the vents. Also, interestingly, the
compressor is never on for more than 2 or 3 seconds, then is switched
off, then back on then then off...and so on and so on. With the AC
running on low (after going through the entire temperature range and
back down) I cycled through the diagnostic channels. I watched output
from channel 7 and 17. Channel 7, the figure on the right is a full
3, the left one is a 1 with the lower segment coming on and then
going off as it should be to indicate the compressor working. This
did not happen before. Channel 17, I think, has given me a bigger
clue. It has 1 complete digit and a dot, the dot indicates when the
compressor is running or not. As is to be expected it comes on for
about 2-3 seconds, then switches off and then keeps cycling like this.
The segment that lights up when the dot goes out is the centre segment
of the digit. It is marked as "Low Pressure Switch" in the fault
code tables that I downloaded and printed.  It therefore seems a
low pressure situation causes the compressor to disconnect and that's
why I'm not getting any cooling. The temp sensor was definitely
faulty, I disconnected it and used the 2nd  best fixing agent (duct
tape) to prevent it from flapping around in the firewall.

When I looked at  the evaporator there is a large metallic canister
in front of that big black box I now know as the evaporator. A pipe
runs into it that leads back to the radiator area (ie. from the
compressor). All the pipes are covered in a sticky black goo, which
I think is just insulation. But it is particularly sticky at the point
where it enters the canister. I think this is the damn thing that
has leaked. About 1.5 months ago I took this thing in and had the gas
replaced. The guy checked the evaporator area by spraying bubbles
all over my equipment in the firewall, didn't seem as if he found
anything. So I paid my US$50 to put in the gas. One week later it was
dead and has been dead since.

I guess the next thing for me to do is take it into a specialist and
have him check for a proper leak, right?

Another note, now that the temp sensor in the firewall has been
disconnected, when I pulled off this morning and checked the outside
temp  reading it came up -1 celcius. Admittedly I did check after
having the motor on for something like 1 minute. Does that temp
sensor at the grill need some time to adjust? If so, then how long?

> '91 200q  parked where it really _is_ 5 Celsius today :-(

'Tis gonna be 30 celcius here today. I'd rather have it cold outside
'cos my heater works in the car, than have it hot outside when my
aircon doesn't! :)

Thanks for the help.

G.

PS: Aleksander, almost the entire edge of that black plastic is
    cracked or broken anyway. It would seem the previous owners and
    their "technical staff" were fiddling there before. :) I'm just
    using the black rubber seal now, I only have metal clips near the
    fuse box anyway.
-- 
"a thousand miles from here, there is another person smiling"
1990 Turbo (200T)
name   : gerard van vught
tel    : +27-57-912 2658 (w) / 082 923 9609 (cell)
url    : http://www.acenet.co.za/homepages/gerard/
e-mail : gerard@poboxes.com  / han.solo@galaxycorp.com
         gerard@acenet.co.za / van_vught@frg.issi.co.za