My '91 Accord is going strong – bought it new in '91. A few years ago I removed the AC compressor after it failed and did not want to incur the cost to replace it. As a result the defroster does not work optimally. Any ideas on how to improve the defrosting without being able to run the AC? Thanks.

On modern cars, the compressor runs in conjunction with the defroster to provide drier air that absorbs the moisture better. However, we had defrosters in cars before air conditioning. Be sure to have the system set to bring in outside air rather than recirculate the inside air. The highest speed setting for the fan should be selected. You can get a defroster fan that mounts on the dashboard in the auto parts section of stores like WalMart. I had good luck mounting two of these cheap fans on the package shelf to defrost the rear window of my slope back 1978 Oldsmobile Cutlass Salon that had no rear window defroster.

We had defrosters before AC, but then, cars had much larger fresh air intakes. I remember cars that would feel like a wind tunnel when the windows were up, fan off and going at highway speeds. Todays cars are designed for AC so the fresh air intakes are much smaller and hidden under the cowl where they draw in air as well as those old pop up vents.

When you get enough air moving, the defrost works a little better, but with your car, you will need a new compressor to get the defroster to work at its best.

I agree with selecting high fan speed on defrost and making sure the vent is set for fresh air with heat on high. However, those cigarette lighter heaters are a waste of money.

@BustedKnuckles-- I agree that the cigarette lighter heaters are a waste of money. The heating element also draws quite a bit of current. However, just a 12 volt fan moves quite a bit of air. These were used for years, and still may be used in buses and trucks with large windshields. I installed one to help defrost the windshield on my 1961 Corvair.

Cars are much tighter especially without vent windows. Everyone want a tight, quiet, sealed car. You need AC to full fill that need. You can get by without AC but you will never have optimum defrosting without it…deal with it. The suggestions are well intended and will help some, but you will never be as satisfied without air…that includes the ones waaaay back in 91. And yes, we had defrosters before AC, but they all stunk compared to those with.
Frost forms on below freezing surfaces from the moisture in the air. It’s a loosing battle to heat all single pane windows in a car for good vision. What about all of the side windows that don’t get direct air flow ? You help minimize the effect by lowering the humidity of the air. It’s a two prong effort. You are are only working with one.
@Keith is right ! You could ride alone, wear a rubber suit and hold your breath…;=(

Crack the front windows an inch or two, you’ll be surprised how much that helps.

+1 to ASE’s post. That’s what I always did in the old days. And before that we used our “vent windows”.

But don’t expect it to work as well as having AC. Sometimes whether something works “well” or not depends upon expectations.

I remember riding in my Dad’s 1939 Chevrolet and 1947 Dodge that had recirculating heaters–little boxes under the dashboard that contained a small radiator and fan. Defrosting in these cars was terrible. His next car, a 1949 Dodge, did bring fresh air in from the outside and heat it. Defrosting was much better. However, air conditioning is even better. I was riding with a colleague in his 1963 Mercury Meteor when the windshield fogged up. He had the defroster on, but it wasn’t clearing the windshield. I suggested he turn on the air conditioner (this was in the spring). He thought I was crazy, but he did turn on the air conditioning. The fog dissipated almost immediately.