Radiator fans do not turn on, overheating

Tiny
APRILSHOWERS007
  • MEMBER
  • 2006 HONDA CIVIC HYBRID
  • 1.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 350,000 MILES
Okay, after overheating damaged radiator, heater core. I went in and replaced everything I could with the cooling system due my car's mileage (over 350,000). Replaced radiator, heater core, water pump, thermostat/gasket, two temperature sensors, but car is still overheating. The only things I did not replace are the cooling fans, because these were easy to verify that they work. They both turn on with AC on. I have tried cross connecting the temperature switch connection with paper clip and fans do not turn on. I have checked relays and fuses, they seem okay. Not sure that I checked the correct ones though. All the diagrams I have found are for the normal Honda Civic and not the Hybrid. What are the specific fuses and rRelays associated with the heating system in my Honda Civic Hybrid? Thanks, Ray
Tuesday, September 18th, 2018 AT 1:07 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi and thanks for using 2CarPros. Com.

I have attached five pictures below. Pictures 1 and 2 show the wiring schematic for the hybrid. The remaining pictures correlate with the following testing and inspecting directions.

___________________________________

Radiator Fan High Speed Circuit Troubleshooting
1. Check the No. 7 (20 A) fuse in the under-hood fuse/relay box. Is the fuse OK?
YES - Go to step 2.
NO - Replace the fuse and recheck.

2. Remove the radiator fan relay from the under-hood fuse/relay box and test it.
Is the relay OK?
YES - Go to step 3.
NO - Replace the radiator fan relay.

3. Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 4.
NO - Repair for an open in the wire between radiator fan relay 4P socket terminal No. 1 and the under-hood fuse/relay box.

4. Connect radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.
Does the radiator fan run at high speed?
YES - Go to step 5.
NO - Repair for an open in the wire between radiator fan relay 4P socket terminal No. 2 and radiator fan motor 2P connector terminal No. 2.

5. Turn the ignition switch ON (II).
6. Measure voltage between radiator fan relay 4P socket terminal No. 4 and body ground.
Is there battery voltage?
YES - Repair for an open in the wire between radiator fan relay 4P socket terminal No. 3 and powertrain control module (PCM) connector terminal A5.
NO - Repair for an open in the wire between radiator fan relay 4P socket terminal No. 4 and the under-dash fuse/relay box.
____________________________

I hope this helps. I had to cut the schematic picture in half (hence two pictures) because of its size. It is for the hybrid model.

I hope this helps.

Take care,
Joe
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Tuesday, September 18th, 2018 AT 6:49 PM
Tiny
APRILSHOWERS007
  • MEMBER
  • 2 POSTS
Thanks, I will perform these tests when I get home tonight. I am driving the vehicle with AC on with high temperature and high fan, just to keep fans on and prevent overheating. Seems to work for now, but hot air blowing in your face is not fun.
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Wednesday, September 19th, 2018 AT 9:39 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I agree. Not sure where you are located, but it has been hot and humid here. Let me know what you find.

Take care,
Joe
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Wednesday, September 19th, 2018 AT 5:31 PM

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