1986 Corvette Cooling Fan
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1986 Corvette Cooling Fan
What is the factory thermal switch setting?
I flushed the fuel rail and fired up a 10+ years sitting C4. Came right to life. Ran it till smoothed out and Temps went to 220 deg. I shut it off and wondered why the fans did not come on? Did some research on the Factory Temp switch setting (for a single fan car) and I found it out to be 239 deg? Is that right? I did the AB test and the fan ran. Does the AB test the relay too? and would grounding the thermal switch wire turn on the fan?
I flushed the fuel rail and fired up a 10+ years sitting C4. Came right to life. Ran it till smoothed out and Temps went to 220 deg. I shut it off and wondered why the fans did not come on? Did some research on the Factory Temp switch setting (for a single fan car) and I found it out to be 239 deg? Is that right? I did the AB test and the fan ran. Does the AB test the relay too? and would grounding the thermal switch wire turn on the fan?
Racer
Joined: Aug 2014
Posts: 478
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From: Elizabethtown, NC
What is the factory thermal switch setting?
I flushed the fuel rail and fired up a 10+ years sitting C4. Came right to life. Ran it till smoothed out and Temps went to 220 deg. I shut it off and wondered why the fans did not come on? Did some research on the Factory Temp switch setting (for a single fan car) and I found it out to be 239 deg? Is that right? I did the AB test and the fan ran. Does the AB test the relay too? and would grounding the thermal switch wire turn on the fan?
I flushed the fuel rail and fired up a 10+ years sitting C4. Came right to life. Ran it till smoothed out and Temps went to 220 deg. I shut it off and wondered why the fans did not come on? Did some research on the Factory Temp switch setting (for a single fan car) and I found it out to be 239 deg? Is that right? I did the AB test and the fan ran. Does the AB test the relay too? and would grounding the thermal switch wire turn on the fan?
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"as long as you ground the correct one "
Thanks for the reply and Information. The wire between cylinder 1 and 3, Green with yellow stripe and has a clip on it that looks like it will break if you touch it.
Thanks for the reply and Information. The wire between cylinder 1 and 3, Green with yellow stripe and has a clip on it that looks like it will break if you touch it.
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Team Owner
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If the car is original the wire between 1 & 3 should be GRN w/WHT stripe(might appear yellow with age) and that would be for the AUX FAN (pusher) front of the rad/cond module. Do you have the AUX FAN? The connector that looks like it would break should be same in appearance as a knock sensor.
***** If you feel you've a primary fan issue change the CTS in the intake and consider it maintenance. For an '86 it might be considered maintenance to include a new connector.
***** If you feel you've a primary fan issue change the CTS in the intake and consider it maintenance. For an '86 it might be considered maintenance to include a new connector.
Melting Slicks
Joined: Aug 2003
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From: Lakeville MI
For 1986-1989 cars, the main fan is controlled by the ecm with the following on/off switch points (coolant temperature as seen by the ecm). Note: the dash display may read differently since it is driven by a different sensor in a different location in order to create confusion.
226 °F On
220 °F Off
The A/C high pressure switch will also activate the main fan independently of the coolant temperature.
226 °F On
220 °F Off
The A/C high pressure switch will also activate the main fan independently of the coolant temperature.
Last edited by tequilaboy; Nov 30, 2023 at 10:34 AM.
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If the car is original the wire between 1 & 3 should be GRN w/WHT stripe(might appear yellow with age) and that would be for the AUX FAN (pusher) front of the rad/cond module. Do you have the AUX FAN? The connector that looks like it would break should be same in appearance as a knock sensor.
***** If you feel you've a primary fan issue change the CTS in the intake and consider it maintenance. For an '86 it might be considered maintenance to include a new connector.
***** If you feel you've a primary fan issue change the CTS in the intake and consider it maintenance. For an '86 it might be considered maintenance to include a new connector.
As far as the " same in appearance as a knock sensor." Not sure where that is.
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For 1986-1989 cars, the main fan is controlled by the ecm with the following on/off switch points (coolant temperature as seen by the ecm). Note: the dash display may read differently since it is driven by a different sensor in a different location in order to create confusion.
226 °F On
220 °F Off
The A/C high pressure switch will also activate the main fan independently of the coolant temperature.
226 °F On
220 °F Off
The A/C high pressure switch will also activate the main fan independently of the coolant temperature.
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Filled the coolant, in 62 deg weather at idle temp never went above 200. I imagine she checks out. I am moving on to the brakes. I am looking forward to taking it down from the stands and making that 1st Corvette Driving Experience. I am still going back and forth to send off the dash or repair it myself. I have a stuck E brake light and valve cover gaskets to tackle.
Thank for all the help.
UPDATE. I found a ground wire near the right headlight not even attached, I figured someone had a horn issue, I put it back and the Big fan in the front came on at 224 deg.
Thank for all the help.
UPDATE. I found a ground wire near the right headlight not even attached, I figured someone had a horn issue, I put it back and the Big fan in the front came on at 224 deg.
Last edited by Damon 86' Auto C4; Dec 9, 2023 at 01:56 PM. Reason: update