hi im having trouble indentifying a part could anyone help
its on a 1998 s70

 

Looks like the idle control valve.

 

would that have an effect on the engine idling when the rear windshield and mirrors heater button is on

 

I wouldn't think so. The window & mirror heaters probably draw on electric system. Maybe you have a problem with your voltage regulator. Maybe you should check your voltage drain with it on and off. I would think your battery would cover you if your alternator or voltage regulator is not operating properly. Maybe someone else can help with that.