94 Sentra AC problem

[whois]

AC works great on blower speed settings 1 thru 3 but on
highest speed setting (4), the compressor stops and the
AC "on" light goes out. This means there is no cooling
when the blower speed is at the highest setting, but the
blower is working properly. This is a factory installed AC
system that is original equipment.

The two blower fuses check good and the AC fuse checks
good. The AC condenser fan relay works properly when the
compressor is running. With the blower speed set on the
highest setting, that means the resistors are not being used.

After pulling the console panels off, the blower speed switch
appears to be an integral part of an assembly which includes
three levers (inside/outside air, heater temp, duct control).
That means the blower switch is not replaceable as a
single part. Not sure this is a switch problem.

Anyone had a problem like this? It is a 19 year old auto.
What can I do next?

[whois]

Forgot to mention, there are no broken wires on the switch
connector, unplugged and connector looks normal.

Post by whois
AC works great on blower speed settings 1 thru 3 but on
highest speed setting (4), the compressor stops and the
AC "on" light goes out.  This means there is no cooling
when the blower speed is at the highest setting, but the
blower is working properly. This is a factory installed AC
system that is original equipment.
The two blower fuses check good and the AC fuse checks
good.  The AC condenser fan relay works properly when the
compressor is running. With the blower speed set on the
highest setting, that means the resistors are not being used.
After pulling the console panels off, the blower speed switch
appears to be an integral part of an assembly which includes
three levers (inside/outside air, heater temp, duct control).
That means the blower switch is not replaceable as a
single part. Not sure this is a switch problem.
Anyone had a problem like this?  It is a 19 year old auto.
What can I do next?

[AS]

I had the same problem in a 94 maxima. It ended up being the blower
control switch. It has to energize the fan and the compressor at the
same time. Because the 4th speed was hardly ever used, the copper
contacts inside got dirty, and would engage the compressor randomly.

Taking the switch out, disassembling it, cleaning and putting everything
back together got rid of the problem.

In my case, the problem happened when the car was 5 or so years old.

Good luck,

AS

Post by whois
AC works great on blower speed settings 1 thru 3 but on
highest speed setting (4), the compressor stops and the
AC "on" light goes out. This means there is no cooling
when the blower speed is at the highest setting, but the
blower is working properly. This is a factory installed AC
system that is original equipment.
The two blower fuses check good and the AC fuse checks
good. The AC condenser fan relay works properly when the
compressor is running. With the blower speed set on the
highest setting, that means the resistors are not being used.
After pulling the console panels off, the blower speed switch
appears to be an integral part of an assembly which includes
three levers (inside/outside air, heater temp, duct control).
That means the blower switch is not replaceable as a
single part. Not sure this is a switch problem.
Anyone had a problem like this? It is a 19 year old auto.
What can I do next?

[r***@yahoo.com]

AS, thank you for the reply of your experience! Found an almost hidden
clip which allowed me to remove the blower switch and cleaned the
contacts. AC works great now on all blower speeds. Used alcohol to
clean the residue and cleaned the contacts with a pencil eraser.

[AS]

I am glad that your a/c is working well now; it is very annoying when it
does not work randomly.

AS

Post by r***@yahoo.com
AS, thank you for the reply of your experience! Found an almost hidden
clip which allowed me to remove the blower switch and cleaned the
contacts. AC works great now on all blower speeds. Used alcohol to
clean the residue and cleaned the contacts with a pencil eraser.