ACC Problems

I have had ACC problems since buying my 92 9000T. The first ACC had wild variations on the scan parameters that varied from second to second. The flap motors got driven to extremes continually. I junked that ACC. My mechanic gave me one that did cooling well. I bought used ones. They all cool well, but I can't get one that heats reliably. The heat starts OK, but then I must keep turing up the target temp. When I get to HI, I then have to manually turn down the fan and it still too hot. I don't belive the problem is the ACC. None of the ACC unit that I own show any error codes on power up and appear to function normally, except for the lack of heat. If I reset the ACC, sometimes it heat properly for a while, sometime not.

My question is if anyone has a reccomended sensor replacement that might fix this.

Reply to
shaab
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The sensor is mounted in the dash. It's the little circular grille to the left of the ACC just below the passenger seat heater rheostat. Behind there is a little fan that is supposed to suck the cabin air into a temperature sensor. The symptom that you describe is what happens when that goes bad.

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Reply to
Malt_Hound

In message , Malt_Hound writes

After many years of service, the temperature sensor gets full of dust and other rubbish and can give a false reading to the ACC controls. Remove the sensor/fan unit and give it a clean before you go to the expense of buying a new one, you need to pull out the ACC controls or the radio as the unit is extracted out of the dashboard backwards, give it a good clean and a little lubricant on the nylon bushes (not a lot, you don't want a dust magnet) and give it a try - you have nothing to loose apart from 20 minutes of your time.

Hope this helps,

Andy

Reply to
news07

Agree on the clean and lube fix. I had the same problem on my '96 9000 but I bottled out of removing the fan as on passenger airbag models you apparently have to remove the airbag (mounted where that useful glovebox is on earlier

9ks), then pull the radio and/or ACC control to get at the fan. I went for a couple of good long squirts with switch cleaner, then a GENTLE probe with a long cotton bud soaked with the same, and finally a moderate squirt of WD40 to lube things. Been fine for getting on for a year now. If you're not sure whether the little fan is running, gently and slowly insert something small (I used the long probe you often get on aerosol cans) into the fan grill. Poke it in gently a couple of inches and you'll here it rattle against the fan blades if it's rotating. Maybe worth doing this first, as mine spat out quite a bit of dry dust. Perhaps not the most technically elegant solution, but may help as a temporary measure...!
Reply to
Pidgeonpost

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