Ac cycling off & on without the ac switch or light being on.

[BLACK DEATH]

I was back flushing my heater core because it wasn't blowing hot.

So after I put everything back together & started the truck to see if there's any leaks.

I noticed the ac compressor was cycling off & on while I had the heat on to see if it would get hotter, which it did get hot after the heater core flush.

The ac light was not on and I was not using the defrost function.

I pulled the pressure switch and it stopped cycling off n on.

Now this may be a coincidence as I've thought I've felt the ac cycle off & on before today while driving around but when I have the fan on only for the heater, no ac light on.

The ac light does work on the switch also.

So I guess every time I turn on the fan switch, it's activating the ac to cycle.

Ill check this again and see what it does....

Any ideas incase?

[00Silverado4x4]

When you select the floor vents does it push air out the little side vents of your dash for your side windows? If I recall that is also considered a "defrost" setting and would allow your compressor to cycle.

[BLACK DEATH]

I haven't had time to actually look at it yet.

If I recall I think it did it when the selection was the regular vents in the dash.

[BLACK DEATH]

Ok so the ac is cycling off n on with ac button off.

It cycles off n on when in the dash position, dash & floor, both windshields positions.

It does not come on at all when in the floor only position.

Now I am totally lost.... Anyone have an idea?

[CapitalTruck]

The A/C compressor comes on in the following conditions for sure:

 

ANYTIME the recirc button is activated, anytime the windshield defrost position is selected, anytime the A/C button is activated

 

Unknown:

 

When a blend of floor and defrost is selected

Additional- This sound like you have recirc pushed for sure, as recirc won't work when in the floor position.

[BLACK DEATH]

Ahhhh good point, let me try that with it off re circulation

[BLACK DEATH]

That's what it was, thanks

[CapitalTruck]

That's why we're here...