Air conditioner,Erratic Operation

My 98 Maxima GLE A/C works fine on the road,but sit for two a traffic signal and the vents start blowing hot air.I checked the car in my driveway,the compressor pumps approx. two min. the suction line is cold during this brief period,but neither fan runs.I had two shops check the system,both are at a loss since neither shop experienced this problem.System pressure is ok.They feel the problem is electrical,but differ on a solution.One suspects the auto climate control thermostat,the other the presure cut off,or a relay.I question both,as the A/C works fine on the highway.Any suggestions would be appreciated.

If “neither fan runs” concerns the radiator fans, that is probably your problem. If no cooling air is going through the A/C condensor, the high side pressure is going to soar. If the Maxima has a overpressure switch, the clutch will be released when that senses too much pressure. You can double check this diagnosis by putting a box fan in front of the car and seeing if the compressor will stay engaged longer.

I would have the mechanic investigate the reason for the fans not coming on. One or both of the fans should come on when you turn on the A/C. If only one comes on, the other should come on when the engine reaches the coolant temperature set point for its switch. Check the fan fuses and relays as each fan draws considerable current.

Hope that helps.