03 frontier A/C dual pressure switch

[ccdhair]

I cannot get A/C to run unless I ground the relay coil wire. The high cut out sw in condenser is open so I bypassed. Has full charge and fuses are good. Anyone know how the dual pressure switch works? I suspect this may be causing probem?

[Q451990]

The dual pressure switch tells the ECU to not engage the compressor if the pressure is either too low or too high. The ECU also needs to see appropriate inputs from an overheat switch on the compressor and a freeze sensor on the evaporator coil... assuming the system works basically like all of the other Nissans I have researched. Ceck out the FSM for your truck for a full explanation. http://www.nicoclub.com/FSM/frontier

What are your pressure readings? Does it work when you bypass the pressure switch?

Heath
Modified by Q451990 at 2:19 AM 4/5/2009

[ccdhair]

Thanks for that very helpful link. I found that a critter had eaten through the sensor wire at the evaprator.

[Q451990]

Critters are bad... glad I could help though!

Heath