Might be worth checking if the fsm states any resistance values for that temp probe that could be used to check it too.

BTW, the 98 and 99s don't have an electric helper fan like 00+ does. It helps with ac performance in slow traffic.

 

Glad to hear it. As long as the outside temp is up high enough and your fan speed stays up, it shouldn't freeze up at all. If you have issues with it freezing up, you could always switch it to outside air/A/C instead of running it on the MAX/A/C setting to introduce some warmer air to the evap. Mine used to freeze up under just the right conditions even with that temperature probe in place believe it or not. That was when my rear expansion valve was faulty

 

I have a 1998 dodge 3500. The high pressure side is about 200 and the low side is about 40. When the compressor cuts in it takes the low side down to about 20 then cuts out (which takes less than 10 sec.). I replaced the cycle switch (on top of the dryer) and it made no difference. When I unplug the switch and put a jumper wire across the plug the system runs constantly and cools well.The low side stays about 15 lbs. Any ideas ?

 

I would post this in the Ram section, you might get more help there. But it sounds like you're low on refrigerant. It's kicking off because the low pressure is too low, which will end up freezing your evaporator up and you won't get any air in the cab. So I would check that first

 

Thanks I'll give that a try. How high should the readings be then on a hot day?

 

Your expected pressures are gonna vary depending on ambient temps and humidity as well as evaporator inlet temp. Check the fsm for you truck, it probably has some pressure ranges in it. Going off the Durango pressures though they do seem low and the switch seems to be doing it's job.

 

Yeah it depends on the vehicle. My 03 3500 cummins runs over 300 on a hot day on the high side but runs about 30 if I remember right on low. Durangos use expansion valves, the pickups use orifice tubes and they act very different so definitely figure out what it should be in your truck specifically