Engine Issue, Watch My Youtube Video And Give Me Your Thoughts...

[eye.surgeon]

My 1998 chevy c2500 is doing something that may or may not be normal. Pardon my mechanical ignorance here in the description but what appears to me to be some type of clutch for the A/C compressor cycles on and off every 10 seconds or so when the interior vent fan is on, even when the A/C is not turned on. If I turn the interior vent fan off, it stops cycling. Is that normal?

 

Here's a brief youtube video showing it happening...just click on the link...

 

http://www.youtube.com/watch?v=-oBgfvvT0AM

 

EDIT...

 

Now that I've thought about it a while, I think it may be cycling off and on because I had the vent setting on defrost/windshield venting. I tried it on the floor setting and the compressor didn't turn on. Someone can tell me if I'm wrong on that. Kind of bothers me that when I turn the A/C OFF it will still actually run if I happen to set the air vent to blow on the windshield.

[Nytemare]

My 1998 chevy c2500 is doing something that may or may not be normal. Pardon my mechanical ignorance here in the description but what appears to me to be some type of clutch for the A/C compressor cycles on and off every 10 seconds or so when the interior vent fan is on, even when the A/C is not turned on. If I turn the interior vent fan off, it stops cycling. Is that normal?

 

Here's a brief youtube video showing it happening...just click on the link...

 

http://www.youtube.com/watch?v=-oBgfvvT0AM

 

EDIT...

 

Now that I've thought about it a while, I think it may be cycling off and on because I had the vent setting on defrost/windshield venting. I tried it on the floor setting and the compressor didn't turn on. Someone can tell me if I'm wrong on that. Kind of bothers me that when I turn the A/C OFF it will still actually run if I happen to set the air vent to blow on the windshield.

yup...you got it right in the edit there.

GM started doing this in 95 I believe... The use of the AC compressor dries the air inside the vehicle and works much better for defogging...

[Jsdirt]

It's actually better for the compressor to run ... it needs to run to distribute oil, so the more it runs, the less "dry starts". Plus it keeps the o-rings lubed & pliable. Up here in MA, the systems tend to not get used very often, & they go to hell pretty quick. Back in the 90's, it was unheard of to buy a used car that actually had working A/C.

 

But, I'd still trade any modern system for a 70's expansion valve/POA system running R12. Nothing like 30° vent temps. ( in summer of course! )

[eye.surgeon]

OK thanks for your input guys.