Fan problem
03-19-2001, 10:01 PM
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Location: Dillsburg, PA USA
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Fan problem
92 L98 will not run fan(s) at 230 degrees. Primary fan will run if ALDL is grounded or when fan relay is grounded from ECM or AC is on. Replaced coolant temp sensor and sensor reads 150 ohms at 230 degrees. However voltage never drops below 5 volts to ECM from CTS circuit! Secondary fan will run if AC pressure switch is jumpered or fan switch is grounded. Swapped ECMs - no luck. What's up?
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JohnW
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JohnW
03-27-2001, 08:10 AM
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Your primary cooling fan is only activated by the ECM. The secondary will be activated by the temp switch in your passenger side head, and/or the AC pressure switch. They are both independant of each other.
If I were in your shoes (and I have been), and you can not burn your own proms, I would get a lower temp snap switch for your passenger side head. Then wire both fan relay ground activation wires together and to the switch. That way, both fans come on together, and will come on at the lower temp. You can also wire a manual switch to both fan relay ground wires, and manually activate from the dash (I did this for years before burning a custom Eprom and lowering the turnon temp).
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Mike Metzler (Desert86Roc)[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For 86 IROC 305 TPI (406 build in progress) Page
ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, headers, no NOS)
If I were in your shoes (and I have been), and you can not burn your own proms, I would get a lower temp snap switch for your passenger side head. Then wire both fan relay ground activation wires together and to the switch. That way, both fans come on together, and will come on at the lower temp. You can also wire a manual switch to both fan relay ground wires, and manually activate from the dash (I did this for years before burning a custom Eprom and lowering the turnon temp).
------------------
Mike Metzler (Desert86Roc)[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For 86 IROC 305 TPI (406 build in progress) Page
ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, headers, no NOS)
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