Cooling fan not working?

DAVIDCHADNEY

MEMBER
1993 TOYOTA COROLLA
1.6L
4 CYL
2WD
MANUAL
170,000 MILES

I have just replaced the thermostat on my corolla and within doing this I have noticed that the cooling fan does not work. I have hard wired the fan to the battery and it didn't run, so I bought a new fan and have fitted it, which still doesn't run when I remove the thermo switch from the connector, (however it runs when its hard wired obvious as its brand new) I have also changed over the relay and tested the fuses which are good. I have also ground the thermoswitch to the battery and still no movement in the fan, this is the same for the Air Con fan. What else can I check or do. I'm going to test the car with a multimeter

3 Replies

WRENCHTECH

MECHANIC
20,757 POSTS

You need to stop with your creative wiring before you fry something expensive. Those tactics can't be used in these days. These are complicated circuits and if the wrong wire is powered or grounded you will take out some expensive modules.

Here are the wiring diagrams. Start out verifying all the applicable fuses with a test light. One fan is controlled by power and the other is controlled by ground.

http://i1198.photobucket.com/albums/aa448/Wrenchtech/41751731.gif

http://i1198.photobucket.com/albums/aa448/Wrenchtech/41751732.gif

https://www.2carpros.com/images/external/41751733.gif

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Sunday, November 2nd, 2014 AT 6:25 AM

DAVIDCHADNEY

MEMBER
5 POSTS

Thank you for the diagrams. I take it that the cooling fan is the one run from ground due too there only being a single wire to the thermoswitch? I have checked continuity on all fuses and they are still intact with a below reading of 0.3 ohms. I am really struggling to get to grips with the wiring as everything is enclosed and packed together. I know I shouldn't be hard wiring stuff, however when I hard wired circuit 1 and 3 connecters with in the relay box there was a buzzing noise coming from the separate A.C relay panel, is this a tell tale sign of anything?

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Monday, November 3rd, 2014 AT 4:13 AM

WRENCHTECH

MECHANIC
20,757 POSTS

This is a complicated, multi speed fan circuit that utilizes 3 different relays to operate these fans. One of thew relays jobs is to flip the ground under certain conditions so you definitely don't want to be running any hard wires here. You could have a working fan one minute and a relay triggers and you suddenly have a dead short and a car on fire. You need to let an electrical expert sort this out.

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Monday, November 3rd, 2014 AT 3:14 PM