98 Blazer no a/c light flashes 3 times

I have a friend with a 98 Blazer with Comp.ClimateControl, the A/C light flases three times but won't engage. I tried different combos of control settings. What am I missing?

Is the system full of R-134a?

You can read codes with a good engine/body capable scanner.

Has anything been done to or changed on sytem?

I don't know if it's charged yet or if anything was changed. The manual says if it flashes three times one of the control settings is wrong but I tried several combinations. Would the system reconize low R134A? Something is not giving it the okay to engage thus no compressor clutch engagement.
Thanks.

Yes a body/AC capable scanner will set and read codes and tell you the problem.
Get code and post back code.


Or you can check R-134a charge.
With compressor jumped and running post back you low and high side readings at idle and at 2K.

With a ac recharging gauge set.
Like one of these.

http://www.ackits.com/merchant.mvc?Screen=CTGY&Store_Code=01&Category_Code=RefrigerantGaugeSets
http://www.ackits.com/merchant.mvc?S...ory_Co de=DIY