Defrost

[korman100]

It seems that when I turn the defrost on and then back to the normal setting that the AC stays on. By on I mean that even after I hit the AC button (which stays lit after you turn the knob from defrost to normal vents) to turn off the AC cold air continues to blow. I know it is AC air because you can hear the AC system still working to cool the air......it is not just the fan blowing fresh air from the outside. Does anybody else have this issue?

[NissanTech]

My Frontier did the same thing.It something Nissan does.If you turn defrost off a/c compressor will still cycle till you turn vehicle off.

[korman100]

I never noticed it on my 85 nissan 720, 1990 240sx, 1995 240sx, 1998 pathfinder.......

[jburson250]

Yep, found this same undocumented "feature" on my LE CC. Haven't checked it out yet on my son's SE KC, but I'm pretty sure I know the answer already. Thanks for posting a thread on this. Once I figured out what it was doing, I kinda forgot about it.

[meckman]

I believe the reason A/C compressor runs is because there is a canister in the A/C line that removes moister from the air. It's a little weird, but I believe most cars work this way. The reason most of us think that it’s weird is because other manufactures don't light up the A/C light on the dash panel. They only light up the defrost light, but behind the seen everything is working the same.

[SPLATT]

I have the same issue. Once I run in the defrost mode, no matter what setting I place the selector knob to, the damn compressor will not stop running. I can turn the fan knob to the off position and the compressor still runs. I have to actually turn the engine off to break the cycle the climate control system is stuck in. Yet another frustrating problem with my Titan.

[Slappy]

The compressor turning on will help to defrost the windows sooner as it de-humidifies the air in the cab.

[homer]

Years ago I was having the AC serviced on my Firebird and the mechanic told me that the compressor would cycle with the defroster running on GM vehicles. He claimed that the compressor contained a small amount of lubricant that kept the rubber hose from drying out because it was forced to the top when the compressor was running. This was the source of many AC systems losing refridgerant, and by forcing the unit to cycle in cold months when you were running the defroster you kept the hose from drying out and cracking. Made sense to me at the time, don't know if it's bs or not, but I do know that my Camaro cycles when the defroster is running. Maybe the same logic applies to Nissan systems? It doesn't make sense to me that it would continue to run after switching the setting, though.

[Titan1027]

love ya all but Ill just keep quit LOL

[korman100]

Just returned from my first 3750miles service. I brought up my defrost issue with the tech. He said the a/c is supposed to come on when you turn on the defrost. I almost punched him in the nose. He just like the service advisor failed to listen to me completly about the a/c compressor running and running no matter what setting you put the selector knob on after you turn off the defroster. Once I explained it I actually had to show him inside the truck. He told me to give him 5 minutes and he would look at it. 10 minutes later he said that is the way the defrost was supposed to work. It will work that way until the key is cycled through on, off, then on again.

Anyone heard the same explanation......or am I getting jerked around????

[IMADOGMAN]

Originally Posted by korman100

It seems that when I turn the defrost on and then back to the normal setting that the AC stays on. By on I mean that even after I hit the AC button (which stays lit after you turn the knob from defrost to normal vents) to turn off the AC cold air continues to blow. I know it is AC air because you can hear the AC system still working to cool the air......it is not just the fan blowing fresh air from the outside. Does anybody else have this issue?

Read your owner's manual (Section 4 page 14). It describes how your defrost "should" work. I would have copied it, but the icon's on the online Owner's Manual, wouldn't copy to the clipboard.

[SPLATT]

I'm still working on the a/c problem. I'm taking my truck to another Nissan dealer today. I'll explain the problem to this set of techs and provide them a demonstration. I'll post their response, Standby...

I can't believe that each and every time the defrost mode is selected the truck has to be turned off and then restarted so that the a/c compressor will not cycle in modes other then the defrost mode. What the hell kind of engineering is that?

[AJfireman]

The owners manual states, if you stay in defrost more than a minute the only way to turn off the a/c is to turn the truck off, something like that. It bugged the hell out of me, till I dug out the owners manual. Silly design.

[bestatchess]

Wow that is dumb. That could be beating down some peoples' MPG.

[KHShapiro]

mine doesnt do that, even after i use the defrost i can turn my a/c off and i know my compressor isnt running