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Old 25th April 2021, 11:54   #1
TheTransporter
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Exclamation Rad fan woes

Hi all, I have a 54reg ZT 135+.

The rad fan hasn't worked in my year of ownership, and the condenser was clearly hole'd.

So yesterday I fitted a new condenser, and replaced the fan.

The replacement fan came from a doner car, and was working fine yesterday morning.

I fitted it to my car, switched on the ignition, and the fan started.
1 second later it stopped.

I wondered if the outside temp sensor being unplugged, due the the front of the car being stripped, was the reason, so I rebuilt the car.

Again the ignition was turned on, and the aircon was switched to demist.. and nothing, the fan was dead.

The ignition was turned off by my helper, and the fan then sprang into life... for less than a second.

I tried bridging the trinary connector... nothing.

I can hear the relay in the fuse box clicking, so that works.

I am at a loss.

Would lack of refrigerant in the system cause issues?
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Old 25th April 2021, 12:02   #2
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I presume the donor car was another diesel, the relay box on petrol and diesel fans are wired differently and not compatible.
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Old 25th April 2021, 12:06   #3
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Yes Steve, same car as mine, just a pile of rust.
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Old 25th April 2021, 12:11   #4
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Also there are no signs the ECU has ever been wet. The plenum are bone dry and the pollen filter has no sign of being wet.
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Old 25th April 2021, 12:40   #5
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Quote:
Originally Posted by TheTransporter View Post
I can hear the relay in the fuse box clicking, so that works. I am at a loss.
Hello Marc,

The relay in the fuse box has nothing to do with the radiator fan.

Is this a 2 speed with resistor or 3 speed fan motor?

Have you soldered the motor wires to those entering your original control box?

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Last edited by SD1too; 25th April 2021 at 12:44..
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Old 25th April 2021, 12:55   #6
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Hi Simon, thanks a lot for your reply.

It is a 2 speed fan, with the gold resister in place.

No the control box hasn't been touched.
I tested the fan via the demist button on the doner car, and it worked, so I unplugged it, and moved it to my car.

They were parked next to each other, so we stripped both vehicles, and then swapped the fans.
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Old 25th April 2021, 13:16   #7
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Ah, thanks Marc, I didn't realise that you'd fitted the fan motor and control box as an assembly.

You may be right about the refrigerant but I couldn't say for sure. To benefit from a working fan you will need a fully charged air conditioning system anyway so why not book a mobile self-employed specialist to pay you a visit?

Alternatively, so long as you don't start the engine, you could bridge pin 1 (black/red) and pin 4 (red/black) on the trinary switch to simulate a full refrigerant charge. You should then hear the compressor clutch engage and the fan start running.

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Last edited by SD1too; 25th April 2021 at 13:56.. Reason: CORRECTED MISTAKE IN PIN NUMBERS
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Old 25th April 2021, 13:50   #8
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Thanks Simon, I will pop out in a minute and give that a go.

I have a mobile aircon fella coming in a few days to test for leaks and regas, so I'll keep this thread updated.
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Old 25th April 2021, 14:20   #9
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Thanks Simon, I will pop out in a minute and give that a go.

I have a mobile aircon fella coming in a few days to test for leaks and regas, so I'll keep this thread updated.
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Old 25th April 2021, 17:42   #10
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OK, I have bridged the red/black and black/red on the trinary switch with the ignition on... nothing.

I Are there any files under the dash that may have popped, I haven't looked there yet.

On the plus side, I've fixed the airbag light.. again.

I have also popped a new pump in for the headlight washers... and that isn't working.

I am beginning to lose patience.. I have a week off of work, so I think I will spend tomorrow fishing, then come back to the car on Tuesday.
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