My blower fan doesn't work until the car warms up a little bit. Same thing goes for the defrost. Once I do get going it works fine, but what causes this??

One other thing I noticed is that when I rev the engine on idle the blower fan output increases as well. Not sure if the two are connected but thought I'd mention it.

I've got a 2003 Honda Civic with 57K miles on it

 

Are your battery terminals dirty?

 

Its a new battery, but I suspect the clamps need to get cleaned. Whats the best way to do so? Why might this be causing the blower/defroster problem?

Thanks for the response, I really appreciate it.

 

Dirty cables could be the reason your heater blows stronger when you rev the engine. I have no idea why it doesn't blow when the car is cold.

 

I cleaned the clamps and post on the battery. Glad I did because there was a lot of garbage on them, especially the positive clamp. I'm not sure if it made a difference.

I did check and I'm able to run it on all settings so I don't think its the resistor, and I was also able to run it without the car being on. Not sure if I was supposed to do that but it worked.

Any other ideas? Is this symptomatic of a bigger problem?