96 960 Engine sputters above 55MPH - only with AC on

[ta975]

For awhile I had a problem where the a/c would stop working (the compressor
only, not the blower) at speeds above about 55 or so. Now all of a sudden
the entire engine starts 'pulsing' - meaning the ignition goes on and off
several times per second when the car hits about 55MPH but only when the AC
is operating.

Additionally the ABS, upshift and check engine lights flash on and off and
the temp gauge needle bounces widly while this is happening. I slow the car
down, shut the ignition and restart and all's well - until I reach 55 again.
If I run w/out the air conditioner it runs well at any speed.

This is a strange one! Can anyone offer any ideas?

 

[Peter Milnes]

Obviously a component in the a/c controller is going duff. Call in the experts
to sort it out unless you have time and components available to swap out each
part till fault clears.

Cheers, Peter.

: For awhile I had a problem where the a/c would stop working (the compressor
: only, not the blower) at speeds above about 55 or so. Now all of a sudden
: the entire engine starts 'pulsing' - meaning the ignition goes on and off
: several times per second when the car hits about 55MPH but only when the AC
: is operating.
:
: Additionally the ABS, upshift and check engine lights flash on and off and
: the temp gauge needle bounces widly while this is happening. I slow the car
: down, shut the ignition and restart and all's well - until I reach 55 again.
: If I run w/out the air conditioner it runs well at any speed.
:
: This is a strange one! Can anyone offer any ideas?
:
:
: