Radiator cooling fan operation
Thread Starter
Instructor
Joined: Nov 2009
Posts: 130
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From: Wentzville mo
Radiator cooling fan operation
I have an 86 that I put a 383 in with a chip that was tuned for it. The AC worked before the new engine. Now the fan for the radiator will not kick on while the compressor is running. Checked green wire with yellow stripe and getting 12 volts to ECM but no fan. Fan wiil come on with engine temp. Is this programming or something else?
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
The cooling fan is controlled by the ECM using the coolant temperature sensor on the front of the intake manifold. It turns on the fan at 228°.
The ECM also has an input from a switch in the A/C lines near the evaporator. There are two switches next to each other. The smaller of the two is the ECM switch. It closes at 190 PSI and opens at 233 PSI. The switch will not close if the system is low on refrigerant or if the pressure is too high (overcharged).
You can turn on both cooling fans by shorting pins A & B together on the ALDL connector.
The ECM also has an input from a switch in the A/C lines near the evaporator. There are two switches next to each other. The smaller of the two is the ECM switch. It closes at 190 PSI and opens at 233 PSI. The switch will not close if the system is low on refrigerant or if the pressure is too high (overcharged).
You can turn on both cooling fans by shorting pins A & B together on the ALDL connector.
Safety Car
Joined: Jan 2004
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Intermediate
Joined: Oct 2010
Posts: 45
Likes: 1
From: Oak Grove Island Georgia
The PCM can be programmed to bring the fan on at various temps. Mine is set for 205 as I spend time in traffic. As I understand it, the other folks are correct in what they say. But you can make the adjustment to the PCM. When I did a dyno tune I had the temp adjusted. Works great and I need no special hardware.
Last edited by stevbullock; Jul 20, 2013 at 01:40 AM.
