Yes, most cars today have two computers (at least). The PCM is the powertrain control module, which controls the engine functions, and the BCM, body control module, which controls accessories such as heating and a/c, and increasingly it even watches over things like power locks, power windows, interior lights, etc. This is what gives functions like "retained accessory power," where the radio and other stuff keeps running for a while after you shut the car off (until you open the front door), and "battery rundown protection," which will shut off interior or exterior lights after a period of time if they're accidentally left on. When you turn on the a/c, that doesn't directly trigger a switch in the a/c system. Instead, you are putting in a request to the BCM, and if various conditions are met, such as engine not being overheated, RPM not above a certain level, etc., the BCM will in turn start the a/c compressor. But all of this is pretty irrelevant to the average car owner like you and me, because if these modules are bad, there isn't much we can do about it. The good thing is, however, that they very rarely fail. Most likely you BCM is working right, and some condition that it's checking for in the a/c is not being met, such as it might have insufficient refrigerant, or maybe there is a sensor that's bad which is giving the BCM faulty data. Bottom line is, you really need to take it to someone who can test it and see what's going on.

I checked and replaced the filter. But now if I turn on the air conditioner and then turn it off, the outside unit continues running, it should not be. (Is this a contactor problem?) Thank you very much for your help. Yes it 'could' be a contactor problem, but it could also be some other problem that causes this action. You've already guessed a few times and are no closer to fixing this. It may be something as simple as replacing a contactor. But this part is an important part that controls your AC. It would be better to call a licensed HVAC contractor to solve this problem and possibly identify another problem with the upstairs zone control. Zone controls are more complex, really not intended to be home owner serviced. It sounds to me like you have more than 1 problem with your zoned AC system. I service the Katy, Texas area.

Hi chemicals that'd curl yer hair, As I mentioned, this seems a useful strategy for Canadians as an alternative to a tax-deferred retirement fund. Here, if I borrowed to invest in the tax-deferred retirement system, interest paid on the loan is not deductible. If I borrow to purchase stocks outside of the tax-deferred system which have a good possibility of being profitable, the interest is deductible. When in regular account I buy Canadian stocks that pay dividends, I pay tax on them at a much lower rate - 4% interest earnings and 3% dividend earnings produce about the same after-tax result. If that dividend income is in my tax-deferred account, that tax benefit is lost. If I invest to earn interest, usually the value of the underlying asset, while it can't shrink ... ... it can't grow, either. So - all that it will ever earn for me is earned - NOW! And taxed now - at top rate. But - the value of the underlying asset deteriorates each year, due to the depradations of inflation ... which means that I must put part of current earnings with the asset in order to preserve purchasing power. I expect that you've read my story about the two rats that eat your cheese. But - if I borrow to invest, and pay interest-only on the loan each month ... ... a few years down the road, I pay back precisely the number of dollars that I borrowed. Each one of which will buy less than when I borrowed it, so I gained from inflation. One wants solid, strong companies in his/her projectred retirement fund, and share prices of such companies tend to stay more stable during down markets ... especially if they are paying a fairly good dividend. If I buy a stock inside of the tax-deferred account, when I sell it, if before the time that I'm to withdraw it, I pay no tax on the capital gain, either, at that time. But the problem is - that when I withdraw funds from that account, which I must do, beginning at age 70, I must add every dollar to my income at the time that I withdraw, with no deductions - and whether or not I'd prefer another course of action, e.g. if I had a substantial other source of income in one year, to put me into a higher tax bracket. And I'm required to withdraw an increasing percentage annually, to 20%, I think it is, at age 90 and at that rate annually from then on. In the regular system, if prices of the stocks that I've bought go up, when I sell them (or die) I deduct the amount that I paid originally, then pay tax on half of the gains, at regular rate - but I pay no tax on half of that gain. When I invest in stocks inside the tax-deferred system, I lose the tax advantage of both the dividend tax credit, and of the deductibility of half of the capital gain. If I hold those quality stocks for long periods, which I tend to do, I don't have to answer to the income tax people till I sell them, which gives me most of the advantage gained by the people who use tax-deferred retirement accounts. When the value of my assets increase, I laugh some. If they go down, I cry a bit. I don't want to be in a position where I must get out at a time not of my choosing. And as I showed you in the message to you the other day - the major composite index in the U.S. has always been up in the last 50 years, give it a 10 year span. You expect to be around for more than that, don't you? If not - no doubt your kids will ... and if they inherit a stock that's doing well, they'll not likely dump it. However - if I buy a chunk of the index here, I can't get share certificates issued, which means that I can't use them as collateral for a loan at the bank - but I can from the broker (as far as I know). Broker's interest rate charged is usually about 1% above the rate that the bank charges. Ideologically speaking, I'd rather do business with the local credit unions, but the rates that they charge are usually substantially higher than those charged by the bank. I've had gains, and I've had losses, but I've never been caught where I had to sell stocks when the market was low in order to keep the bank off of my tail. As some people in the investment group that I've attended for years say - "Losses are the tuition in the learning-how-money-works game". Good wishes for your skillful participation in that game. ole joyful

Hello! Window air conditioners provide a more permanent option that's short of installing central AC. They're not quite plug-and-play but can still provide cost and time savings while giving you the option to relocate the window AC unit in the future. The primary utility of an air conditioner is the comfortable cool air, there are many other health benefits of air conditioning aside from some health risks.Recently I've found best ac in dubai as it was impossible to survive in such a hot weather. Thanks to the experts I bought the most appropriate option for my house and believe that you'd find it too!