2003 Tahoe, RPMs jump from 600 to 800 every 8 seconds and AC clutch spins when climate controls are turned on.

[76Nick]

So I am having a weird issue with my 2003 Tahoe Z71. At idle when I turn on the climate controls (even with the AC off) the AC compressor clutch spins for a couple seconds and the RPM's jump from 600 to 800. Then the clutch stops and the RPM's go back to 600. This happens about every 8 or so seconds. I am showing no codes at all except for a catalyst code which I've had for a while. Anyone have any idea what could be causing this?

 

[rockola1971]

Try disconnecting plug at compressor and see if the RPM problem goes away. If so then I suspect you have a shorted (melted together clutch coil). Have automatic or manual hvac controls? Auto has the digital temp readout for driver and passenger settings.

 

[76Nick]

Try disconnecting plug at compressor and see if the RPM problem goes away. If so then I suspect you have a shorted (melted together clutch coil). Have automatic or manual hvac controls? Auto has the digital temp readout for driver and passenger settings.

I'll give that a shot thanks. I have the auto hvac controls...do you think the controls may have something to do with it?

 

[justirv]

I'll give that a shot thanks. I have the auto hvac controls...do you think the controls may have something to do with it?

There is a chance that the controls are the source of the problem. As @76Nick says, start at the compressor and work your way backwards. I suspect that your refrigerant level may be low, and what you are seeing is constant A/C (clutch) engagement, with low-pressure (refrigerant) cycling.