I don't have a way to check the system pressure without taking it to a shop, and I don't want to do that unless there's something wrong.

When I have my heat and defrost on, the A/C compressor will engage, spin for 4 seconds, and release for 6 - 7 seconds, before the clutch engages again for another 4 seconds.

I know for A/C that's far too short and it means there's not enough pressure to keep the clutch engaged. Problem is, I don't know how long the compressor is supposed to be engaged during heat / defrost operation.

Any insight before I make an appointment to have the system leak checked and filled...for the winter.

 

It's normal. The ac cycle's to help with condensation and to keep the system oiled.

 

I knew the cycling was normal, but wasn't sure if a cycle that fast was a sign that the system is low on coolant. I remember when the system was low on coolant last summer, the compressor cycling was around 4 seconds like it is now.

 

Go buy a r34 refill kit from walmart. They are like $30 and they come with a gauge so you can tell if it is low. Thats what I do anyways. Beats paying a shop to do it for me.

 

My shop does an A/C charge for $20.

 

OK, if you can find a shop to recharge your AC for $20 then go for it. Shops I use charge a minimum 1 hour labor on top of supplies. Wish I was close to your shop.

 

Shops around here charge between $80 and $100, and that's if they don't charge a fee for just testing.