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The ACC unit on my 1977 9000CSE has developed a noise rather like a relay rapidly clicking in and out. It persists even with the ignition turned off. The only way to stop it is to remove the fuse. Are there any quick fixes or will the complete unit have to be replaced. Advice greatfully received :
 

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I have had this twice on different cars, and fixed it in both cases by taking the Cabin air temperature sensor out,(this is the unit mounted in the dash near the steering wheel with a plastic grid over it), cleaning away all the dust and then squirting with a little WD40.

The unit works by drawing air in past a thermistor or temperture sensitive resistor, which then sends info to the ACC unit. As it is constantly drawing in air it obviously draws dust and hairs etc from the inside of the car and needs cleaning out every now and then.

It starts as soon as the key is turned and remains spinning for about 90 seconds after stopping.
 

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Welcome to the board John E!

I tend to agree with cabin temperature sensor diagnosis. Mine makes strange noises even after cleaning and lubricating. I think the fan runs for about 4 minutes after turning off the ignition, so if your noise continues for longer than that, it's something else!
 

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As Mark B said, you need to get the unit out backwards:

Pull off the usually blank switch cover next to it which will let you push the ACC unit out easily. With this out GENTLY pull at the back of the sensor, whilst lifting the plastic retaining tabs on the front (remove plastic grid first). It should with a bit of wobbling come out. Then disconnect the electrical block and pass it through the ACC 'hole'
 

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Ok, pulled the grill and blank switch plate out and cleaned the thermistor out but still confused on getting the ACC control unit out. Is this what I need to do or simply slide the sensor to the rear toward the firewall? Sorry, must be lack of sleep or something!!
 

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Originally posted by Griffin #341:
[qb]Ok, pulled the grill and blank switch plate out and cleaned the thermistor out but still confused on getting the ACC control unit out. Is this what I need to do or simply slide the sensor to the rear toward the firewall?   [/qb][/b]
What you have done is enough to keep the thermistor free from that extra insulation of dust and dirt. If it starts squeaking at some future point, then it may be worth taking it out and lubricating it, in which case the easiest way is to remove the ACC unit. Simply take the blank switch off (unless you have TCS), put your finger in and push the ACC unit out into the cabin. You can then gain easy access to the back of the 'sniffer motor' to pull it out towards the firewall.
 
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