SR71BLACKBIRD

Today in Seattle it was about 32-34 F and I had the sun roof open with the heater on at about 23 on the heater dial to keep me warm while I enjoyed a nice sunny Sunday drive. At 23 F on the dial , it was nice and toasty in the car (without the A/C Mode on); but all of the sudden the heat was gone and I was getting cold air.

I get some heat when I turn the heater dial up to 30+ but something is wrong.

Does anyone have an answer to this?

Thanks

Scott

raycm

I thought Monterey Bay was cold but Seattle wins.
The air cond/heater control unit, in the dash, has a fan mounted on its hood side. It draws cabin air across a thermocouple. This tells it what the cabin temperature is. When the fan motor dies the thermocouple sees the temp inside its control box. Pull the control box out of the dash and you'll be able to see this fan spinning. Perhaps a test would be to turn the key on and put smoke in front of the thermocouple opening, on the driver side of the control unit.

Ray

SR71BLACKBIRD

Thanks for the reply Ray. Is the control box hard to take out

Thanks

Scott

raycm

No but you need a special tool. A U shaped rigid wire with notches in the ends. Stick through the 2 holes in the face plate and it releases the latches. Radios use the same tool. I happen to have 2 tools. The one of smaller wire diameter fit this situation. I got these with a car I bought. I understand you can buy these in auto parts stores. My Kragen doesn't have them. By the way, I have a fan motor on order. Mine died.

Ray

raycm

On second thought. :-) You may be able to stick a nail in each hole about 2" deep. Then push from the back or use a thin spring hook to pull on the edges of the panel, face plate. The notches in the tool are supposed to grab onto the unit and allow you to pull it out by the U shaped tools. The nail will release the latch. Tilt the inserted nail towards the closest outer edge of the face plate, and pull with spring hook. You'll see the unit start to come away from the dash. Then do the opposite side. Once both sides come out a little the latches are no longer a problem. By the way don't need to do anything with the *****, etc. All the controls come out with the unit.

Ray

Ray

jnor10

So, if its works correctly, do you to pull the unit and blow some compressed air over the back of the fan to clean the hairballs out?

Sounds like a good preventitive maintenence measure.

Jeff N.

raycm

You can blow air in from the face plate. Its a 3-4" tube with a thermocouple near the face plate and a fan/motor mounted on the back end. If the fan is working, cleaning out the passage allows the sensor to do its job. But getting dirty happens slowly not as you describe a sudden problem. My guess, & your mileage may vary. :-)

Ray

SR71BLACKBIRD

Ray: I am looking at the face plate on the car without taking it off yet but a hole about a 1/4" in diameter that has a molded coarse screen as part of the face plate: I see lots of hairballs and stuff all stuck in that hole - is that what you are talking about? is that where the air is sampled?

All my fans seem to be working. I will try to vaccum the fur ***** out

Thanks

Scott