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Hi all, I’ve read all the topics I can find that relate to the issue that I’m having but none have solved it.

The car has a half rad and the slimline fan is on all the time. I’ve replaced the fan switch and it’s made no difference. Is it likely to be the relay? Seems to work fine though and surely it would fail open? Only other thing I can think of is the AC relay isnt bridged but I can’t find a picture of how to do this. 

Any help would be great

Jase

Edited by Pikey009
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I’m sure the ac rely bridge was only on the gt turbo , I would check the wiring to the fan switch if you replaced the switch and check the relay try swapping it over with one of the others and see if that give you ideas to what’s going on 👍🏼

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Yeah it was only on the GT’s. No other relays fit and the wiring all looks fine but I haven’t had a fluke in there yet. The ac isn’t bridged but the previous owner said the original fan was fine even with the air con removed 

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Is it on an EP82 gt turbo?

If so, have you tried disconnecting the fan switch connector on the thermostat housing and shorting the pin in the connector to ground with a jumper wire? It should stop the fan running. 

Will need the ac plug looping: https://www.toyotagtturbo.com/community/index.php?threads/aircon-removal-guide.27259/

All described in the link above.

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12 hours ago, Pikey009 said:

Yeah a 1992 GT turbo. Thanks v much guys I’ll try both of these When I’m next at work and post which one works, great help. 

Check the A/C relay wire is bridged / has the sensor still plugged into it first as glanzadude posted.

Then try grounding the fan switch connector wire as I suggested. This checks if the fan switch in the thermo housing works / is the correct type and if the plug is connecting to it properly (you said the switch was a different colour plug and didn't connect well.). It could also show if the wire from the fan switch to the relay is broken.

Then its the relay to check.

Snaffled this from a reliable source on the other forum, it describes how an EP82 gt turbo system works:

With your everyday typical relay (normally open) the switch contacts are open until the coil side is energised, the electromagnetic field created by the coil pulls the switch contacts together switching ON the circuit that the relay controls.

The rad fan relay is slightly different, it's a normally closed relay. The switch contacts are closed until the coil side is energised, the electromagnetic field created by the coil pulls the switch contacts apart switching OFF the circuit that the relay controls.

The rad fan thermo switch is connected between body ground and the coil ground terminal of the rad fan relay, it's a positive temperature coefficient switch which simply means that as it heats up it's electrical resistance increases to the point it gives infinite resistance or open circuit if you like.

Assuming all the relevant wiring and components are working correctly, with the ignition on and the engine coolant cold, the thermo switch is closed and earthing the ground terminal of the rad fan relay. This causes the normally closed relay switch contacts to open and the rad fan to turn OFF. When the coolant temperature increases above the thermo switch rating or the connection between the thermo switch and ground terminal of the rad fan relay is broken, the relay switch contacts return to their normally closed position and the rad fan is switched ON.

(Apparently the Glanza system is different.)

Let us know how you get on.

Edited by Claymore
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I’m now away from the car for a week but will try all of this once I’m back at work. I didn’t think I’d get these cracking responses so I thought I’d post the issue now ready for when I’m back. Will let everyone know what works! 

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  • 2 weeks later...

So after reading everything thoroughly on here and having literally only 10 mins to look at the car today, I’d like to rule out the AC connector bridge. Can someone please tell me or show me which one it is as I’ve got loads of disconnected connectors. Here are some:

Edited by Pikey009
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  • 2 weeks later...

So the fan issue is sorted. Basically a good friend of mine sent me pictures of his bridged connector and it turned out to be completely different from his (mine is a 92 and his is a 93). It was only when he showed me where his wire originated from that I knew what connector to bridge. Thanks to everyone for their help 👊

 

This is his

1.jpg

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