Engine fans don't want to come on, 95 Neon
#1
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Did some searching and couldn't find the answer to my little problem. The engine fans won't come on even though the engine is too hot.
1. Made sure the electrical connection was good from the wiring harness to the fans.
2. In pulling the relay, the cover came off, exposing the actual relay. Depressing the relay to make contact and both fans run.
3. No 12v signal coming into the relay socket, therefore it won't actuate.
4. The dashboard temperature indication appears correct - it follows the temperature from cold to too hot. (Does this mean the engine temperature sensor is fine??)
Now I need a little help. This looks like it's either the Control Module or the temperature sensor. The wiring from the sensor appears acceptable (assuming that the sensor is that black thing on the left (driver's) side of the head - a black lump about 2" square with a 3-wire plug and four bolts holding to the head.
If I pull that black square, is there any coolant behind it (will I have to drain the system a bit)? I didn't try the engine with the connector out of the sensor but do the fans actuate with high resistance (an open) or low resistance? If I was going to put a 100 ohm (?) resistor on the plug for a test, which pins are connected to the thermistor in the sensor?
Thanks,
Mike
HOT Las Vegas!
1. Made sure the electrical connection was good from the wiring harness to the fans.
2. In pulling the relay, the cover came off, exposing the actual relay. Depressing the relay to make contact and both fans run.
3. No 12v signal coming into the relay socket, therefore it won't actuate.
4. The dashboard temperature indication appears correct - it follows the temperature from cold to too hot. (Does this mean the engine temperature sensor is fine??)
Now I need a little help. This looks like it's either the Control Module or the temperature sensor. The wiring from the sensor appears acceptable (assuming that the sensor is that black thing on the left (driver's) side of the head - a black lump about 2" square with a 3-wire plug and four bolts holding to the head.
If I pull that black square, is there any coolant behind it (will I have to drain the system a bit)? I didn't try the engine with the connector out of the sensor but do the fans actuate with high resistance (an open) or low resistance? If I was going to put a 100 ohm (?) resistor on the plug for a test, which pins are connected to the thermistor in the sensor?
Thanks,
Mike
HOT Las Vegas!
Last edited by Vegas Mike; 05-30-2012 at 07:42 PM.
#7
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#8
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Didn't get the pictures. Did they go to mike.ramay@ gmail dot com??
I jury rigged the fan relay to turn the fans on and off again with the ignition switch. Turns out that the power to the fan relay is supplied when the ignition is turned on and then the control module either supplies a ground for the relay (fans on) or no ground (fans off). Using a spare relay, I bent the #85 spade out to the side so it didn't go into the plug and then just ran a short wire from that spade to the ground side of the battery. Now when the engine is started the fans come on and then go off when the engine is switched off. Not pretty but it's 104F in Vegas today and this will let the car work until "we" figure out how to fix it.
Thanks,
Mike
I jury rigged the fan relay to turn the fans on and off again with the ignition switch. Turns out that the power to the fan relay is supplied when the ignition is turned on and then the control module either supplies a ground for the relay (fans on) or no ground (fans off). Using a spare relay, I bent the #85 spade out to the side so it didn't go into the plug and then just ran a short wire from that spade to the ground side of the battery. Now when the engine is started the fans come on and then go off when the engine is switched off. Not pretty but it's 104F in Vegas today and this will let the car work until "we" figure out how to fix it.
Thanks,
Mike
#10