Cooling Fan Woes
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Joined: Mar 2009
Posts: 60
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From: Memphis TN
Cooling Fan Woes
My main cooling fan was not working (high temp or A/C on), so I replaced the relay. Now the fan runs constantly. Where is/are the sensor(s) that should make it cycle?
Thanks
Scott
'89 Convertible
Thanks
Scott
'89 Convertible
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
The relay is simple. It gets a signal from a sensor or ECM thru a complete ground path, energizes the relay that completes the ground path for the fan motor. You can test the fan by grounding the temp sender with a good relay. If its stuck ON...that tells me the ground is shorted at the temp sensor, OR the relay itself is stuck, wrong or grounded out. Look at the section of wiring harness for damage at or near the plugs for the relay and temp sender switch.
Thread Starter
Advanced
Joined: Mar 2009
Posts: 60
Likes: 1
From: Memphis TN
The relay is simple. It gets a signal from a sensor or ECM thru a complete ground path, energizes the relay that completes the ground path for the fan motor. You can test the fan by grounding the temp sender with a good relay. If its stuck ON...that tells me the ground is shorted at the temp sensor, OR the relay itself is stuck, wrong or grounded out. Look at the section of wiring harness for damage at or near the plugs for the relay and temp sender switch.
Pro
Joined: Feb 2010
Posts: 677
Likes: 3
From: Metairie LA
New parts that are defective are nothing new (especially these days). The ECM's temp sensor is on the front of the intake manifold base on the passenger side of the water neck and a little below. It has two wires (my 86 were yellow and brown of I remember correctly).
Melting Slicks
Joined: Jan 2009
Posts: 3,181
Likes: 286
From: Puyallup Washington
I repaired computer systems for about 20 years. One thing I have learned is that new parts are often bad. You went from the fan not running at all to running constantly after you replaced a relay, yet you think it has to be something else. Check the relay!!!!
Thread Starter
Advanced
Joined: Mar 2009
Posts: 60
Likes: 1
From: Memphis TN
New parts that are defective are nothing new (especially these days). The ECM's temp sensor is on the front of the intake manifold base on the passenger side of the water neck and a little below. It has two wires (my 86 were yellow and brown of I remember correctly).
