By Larry Rubenstein
AUTO SCANNER
July 20, 2008 04:47 am Q: I have a 2000 Mercury Sable wagon with 75,000 miles on it. For several years now, on hot days if the car is parked in the sun I have a problem with my air conditioner. Generally the AC works fine, but after sitting in the sun, when I get into the car and start it up , the AC will work for less than a minute and then it will blow very hot air, and short out the radio and clock. The unit that houses the AC/heat control is one panel that also houses the radio/CD/tape and clock. When the AC is not working, that whole panel shuts off, meaning I have no radio, no clock and I cannot control the fan or turn off the hot air blowing out at the maximum fan speed. Once the car is parked in a cooler spot and it has cooled down, the AC is fine. The dealer has replaced the panel that houses the AC, radio twice and also replaced sensors for the AC, but over $1,000 later, it still happens sporadically. If I use the auto setting for the climate control the AC works fine and I don't have this issue at all. A: This is a great question. I did a search of the International Automotive Technicians' Network, and also checked the archives on the AllData Web site. There are no mentions of your problem. I do know the system that's in your car, and I feel Ford did a very poor job with the design of integrating HVAC and radio into one module. What I think may be happening is as follows. As the sun hits the plastic case of the HVAC controls, the housing is expanding and causing a power wire or circuit to short out. To further check this problem, and make an inexpensive repair, go to a discount parts store or even a super store automotive section. When there, purchase a foldable panel that goes up on the windshield of your car on the inside to block out the sun. You can also try leaving a white terry cloth towel over the dashboard area of the controls. So anyway, put this sun blocker in place, and see if the problem goes away.
Q: Twice in the past year, the air conditioner condensation drain tube in my 2005 Subaru Outback has plugged and caused the floor of the passenger front seat to become soaked with water. It is easily cleared by the dealer garage (for a price) but I wonder if there isn't a permanent cure to this annoying problem. The dealer repair supervisor told me that as long as I park under or near a tree the debris, etc. will get into the AC drain tube and cause "occasional" blockage. Since there is only clear water that collects on the floor of the car, I wonder what happens to tree particles, etc. Do the particles somehow need to be discharged through the AC drain tube? I should think the condensation drain for the AC would be only for the AC and not affected by rain-borne particles or anything else and I wonder what is causing the blockage. Can you tell me if there is a cure for this and, if so, is there something I can do to eliminate the problem? A: Your car has a cabin air filter. Quite often the manufacturer leaves the filter carrier empty and you are getting a lot of debris in the HVAC box. This debris will block up the outlet tube. If the filter is there and the filter is clean and this just happens to be the nature of the design, I recommend you use a regular repair shop for your oil changes and I am quite sure, while they are changing the oil they will blow out the tube at no additional cost because you are a regular customer.
Larry Rubenstein is a master technician who owns a North Shore service station. His column appears Sunday in WheelsNorth. Write to Larry c/o The Eagle Tribune, 100 Turnpike St., North Andover, MA 01845, or send e-mail to scanauto@aol.com.
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