1989 Chevy Celebrity computer not working

Tiny
NAVIGATOR424
  • MEMBER
  • 1989 CHEVROLET CELEBRITY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
The radiator fan will not come on I have to unplug the sensor for the fan and it comes on constant I have replace the sensor and the fan relay also replaced the tempture sensor for the dash indictator there seems to be no power from the computer to fan relay or tempture sensor also I changed the plugs and there is alot of soot no oil on them so computer seems not to be working
Thursday, September 3rd, 2009 AT 3:10 PM

7 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
The computer grounds the fan relay in order to energize it. If the fan comes on, when you disconnect the CTS, at least the computer knew you unplugged that sensor.

The info says, over 30 mph, the pcm will disconnect the fan relay ground as long as the ac is not turned on and the engine temp is below a certain temp, 220 something, I'd have to double check the temp.

If you disconnect the cts, the fan should run. If the ac is on, the fan should run. If you use a jumper to access codes, key on, the fan will run. I'd check everything before I suspected the computer.
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Thursday, September 3rd, 2009 AT 3:33 PM
Tiny
NAVIGATOR424
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Why is the engine firing dirty some black sooty smoke on start and soot on plugs up also with the tempture sensor pluged in there is a check ingine lite on
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Friday, September 4th, 2009 AT 11:41 AM
Tiny
JDL
  • MECHANIC
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Sounds like the system is running rich. Check trouble codes, if the lite is on? A faulty cts or wiring circuit might cause the system to run rich?
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Friday, September 4th, 2009 AT 9:21 PM
Tiny
NAVIGATOR424
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THE ENGINE LIGHT IS ON HOW DO YOU CHECK THE ENGINE LIGHT CODES AND NEED THE ERROR LIST SND HOW TO CORRECT
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Saturday, September 5th, 2009 AT 2:22 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS


https://www.2carpros.com/forum/automotive_pictures/170934_aldl_10.jpg



You place a jumper wire between the A & B terminals of the datalink connector. Turn the key just till the dash lites come on, no further. The check engine lite starts flashing, you count the flashes to get the codes.


https://www.2carpros.com/forum/automotive_pictures/170934_89_checy_celeb_code_1.jpg

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Saturday, September 5th, 2009 AT 4:30 PM
Tiny
NAVIGATOR424
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  • 4 POSTS
Now the tempture sensor for the fan is up plugged so fan will run I want to plug the sensor back in so the computer will sense the temp but the fan will stop where is a good place to connect the fan to so it will run constantly when engine is running. I dont want it to sycle on and off
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Friday, September 11th, 2009 AT 12:14 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
You need to fix the actual problem. Were there any codes? You can use a jumper wire at the fan relay connector, relay unplugged, the jumper goes on the connector for the load side of relay.

Just another thought, the voltage for the coil side of fan relay, goes hot when you turn on the key, turning off the key should kill the fan, if you wire it that way.

If you wire it the first way, the fan will run until you unplug something.
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Friday, September 11th, 2009 AT 1:52 PM

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