RE: IML: 71 auto temp II

["Robin Giesbrecht" <robings@xxxxxxxxxxx>]

I have had quite a bit of experience getting my 72 auto temp II sorted out. 
The system was sold to Mercedes and they used it during the late 70's and 
early 80's. I have scavenged several servos and amps from Mercedes at junk 
yards. The system will not function until the coolant reaches a certain 
temp. Then a bi-metallic vacuum switch is made on the bottom of the servo 
and that, in turn, makes another vacuum switch under the right dash beside 
the computer. There is a good write up that I can email to you on setting up 
the servo. If the servo does not work properly the system will not function 
properly. Also there are two vacuum check valves situated along all the 
vacuum lines that run from right side of under dash to the temp control. 
They are at floor level and they are cheap pieces of ####. I replaced mine 
with industrial check valves from a hydraulic shop and finally got my system 
working properly. There is much more to all this but basically you need a 
good servo, good amp, good selector, good check valves(originals probably 
are leaking)and, obviously,a good air conditioning 
system(compressor,evaporator, condensor,etc). The air conditioning part any 
good shop should be able to figure out. The rest, unless he is a real auto 
temp II specialist, will be a little more difficult. As far as I know the 
amp is not known for failure. I would venture a guess and say that your 
check valves are leaking, for one. Once I replaced those I would check the 
servo for correct operation. Not hard if you can use a multimeter. And I 
would disconnect that green vacuum switch under the right dash and install a 
jumper wire in the electrical connector that attaches to it. That way you 
have eliminated two vacuum switches that could be failing(mine did)and it 
gets you that much closer to finding the problem(s).Jumpering this switch 
will not harm the system, just makes everything work before engine water 
temp is warm and , as a result, may give you cold air when you want warm 
when you first start the car.

R0obin Giesbrecht
72 Imperial


> From: Bruce Stubblefield <audiblefeast@xxxxxxxxx>
> Reply-To: mailing-list@xxxxxxxxxxxxxxxx
> To: mailing-list@xxxxxxxxxxxxxxxx
> Subject: IML: 71 auto temp II
> Date: Tue, 1 Feb 2005 12:49:42 -0800 (PST)
>
> Hello,
>      The mighty 71 4-door is in the shop for AC
> repair, and I have a question.   The symptoms are:
> for the entire year I've had the car, the auto temp
> has had two settings, very hot and very cold.
> Thumbwheel to 65 degrees makes very cold,  thumbwheel
> at 85 makes very hot.  Recently the heat vs defrost
> routing has not worked (air out of defrost on both
> heat and defrost, etc. ) The shop seems good and the
> guy doing the car  seems experienced, but they have
> had it for 3 days and haven't found all the problems.
> They say all the vacuume lines held and were ok, and
> that my problems are electrical(freon is full,
> compressor good).   They found the amplifier bad, from
> overheating, which  they say is common with this
> system(which resembles Mercedes systems, apparently
> they copied it, or something).  Amplifier was
> replaced, along with its one-amp fuse.  As of now,  AC
> blows at 43 degrees WHEN IT WORKS.   It's
> intermittant.   He has been able to get the AC to work
> by starting on defrost for a while, then switching to
> AC.   He also says that the relay which keeps the
> heater off until the coolant is hot also keeps the AC
> off until the coolant is hot(meaning, he says it's
> designed that way), which makes no sense to me and
> contradicts the FSM.
>     Any comments?
>
> Many thanks
> Bruce S
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Mail - 250MB free storage. Do more. Manage less.
> http://info.mail.yahoo.com/mail_250
>
>
> -----------------  http://www.imperialclub.com  -----------------
> This message was sent to you by the Imperial Mailing List. Please
> reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be
> shared with everyone. Private messages (and attachments) for the
> Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx
> To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm




-----------------  http://www.imperialclub.com  -----------------
This message was sent to you by the Imperial Mailing List. Please 
reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be 
shared with everyone. Private messages (and attachments) for the
Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx
To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm