[KJB]

I have a 1999 Explorer. I can't get the A/C to blow cold at all. The heater is nice and warm though. BUT...when I have either one on, the truck tries to lurch forward every few seconds. The rpm's increase and then go back down...rinse and repeat. I explored it a little more today, and it seems that it only happens if it is not set to blow on ONLY your face, or ONLY your feet. If the blower is set to those two, it seems to run fine. Any other setting, and it lurches. Including A/C, MAX A/C, defrost, or any mix in between. Can anyone help me out here? Thanks a lot!

 

[electro]

Your A/C refrigerant level is low!
When the level is low, the pressure is low. Your A/C is cycling rapidly as a reflection of this. So either charge and check the A/C, or choose a ventilation setting that does not require the A/C to be on, or unplug the A/C cycle switch.
http://www.fordforumsonline.com/for...-cooling-systems/303-test-c-cycle-switch.html
http://www.fordforumsonline.com/for...ooling-systems/155-c-clutch-clicking-off.html

 

[Poppy]

Boy that was an easy one for someone who knows what he is talking about eh electro?
My first thought was one of the vacuum actuators had a vacuum leak, but there isn't one that would fit the situation. Your response was right on! Good job!

 

[electro]

Sometimes when a components fails there are no easy clues. However, in this case the A/C is hollering out "fix me, fix me" every time it goes click-click-click. Lol.

 

[KevinCro]

It should be pointed out that the compressor will come on under the defrost setting. This is why the vehicle could possibly lurch under A/C or heat.