How to rebuild the radiator fan switching system + Loud fan?

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VectraGoVroom
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How to rebuild the radiator fan switching system + Loud fan?

Post by VectraGoVroom »

So as you may know, I got my Veccy as a birthday present after my brother had fixed her up from a front-end collision. A few utilities got lost on the way, including the radiator fan system. When I got the car, the two fan wires were just hanging loosely in the engine bay with no connector on the end. I've since added a manual switch inside the car to run the fan when necessary, but it's bulky and not very fun to notice I've forgotten to turn it on when sitting in traffic. Also, the fan is really loud, loud enough to drown out the idling engine.

So, how exactly is the fan wired up, all the way from sensor to fan, where is the sensor, and how big a job would it be to get the system up and running again? As to the fan, is something wrong with it making it so loud, or are there different speed settings I just can't use by connecting straight to the battery?

The car's a C20NE with no AC.

Thanks!
Call them Cavs, but mine's a Veccy. <3
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

The fan switch is screwed into the rear right hand edge of the radiator near the bottom.

It should have 2 wires to it.

I have a picture somewhere in my WIP.
Here we go - on page 35.

viewtopic.php?f=21&t=4069&start=850
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Huh, thanks. So I just hook up the fan's negative to ground, positive to the fan switch and battery positive to the other pole on the switch, or is there more to it?
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

It should be just two wires.

a brown / white power feed direct from the control relay.

A brown ground wire.

No need to connect to battery positive.
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

I'm fairly sure all the wiring for the stock fan is gone, so I might indeed have to run power straight from the battery. If the wires are still present, where in the engine bay would they emerge from the wiring loom? Looking at some pictures I have, I think I can see some lonely-looking wires behind and under the battery.

Also, the Haynes manual says to drain the cooling system before removing the switch. Is that actually necessary?
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

I have updated my previous post.

The switch is low down on the radiator.

If you are swapping the switch, as soon as you unscrew it, the coolant will drain out anyway.

If it is just wiring, then no you don't need to drain it down.
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

So where does the fan hook up to? Do I just connect the positive to the ground pin of the switch and ground to ground? The fan has no connector on it, just two wires hanging free. It gets confusing.
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

Okay -
So you have a manual switch inside the car.
This runs the fan fine, but you forget to turn it on at times.

My simple answer is - extend the wires from the manual switch to the radiator fan switch.

Job done.

Or am I missing something?
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Hell, I didn't think of that. Can the switch handle the current draw of the fan?
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

I am surprised you question a purpose made thermo switch when you have used a switch to use in the cabin.

In your situation, I would trace the wires from your cabin switch.
I would guess that these wires would go to the control relay.
If this is true, then you do not need a high ampage switch.

If it goes straight to the fan motor, then you need a switch and wiring rated at 30 amps.

Now then.
If the cabin switch is wired to the relay, I would re-route the control wires out to the thermoswitch in my photograph.

If it goes to the motor, I would indeed wire up a complete circuit in the engine bay with a 40 amp relay.

How would I wire this?

If wiring so that the fan only runs with the ignition on -
Find an ignition live source. (Black wire - there is one in the big round connector near the battery).
Run a wire from here to the thermo switch.
Then from the thermo switch to the relay control pin. Pin 86

If you want the fan to be allowed to run on after the engine has been turned off, then you can link Pin 86 to Pin 30 of the relay.
The reason for this will become obvious in a moment.

A ground wire from pin 85.

A thick wire from battery plus terminal to a 30 amp fuse.
From this fuse to relay pin 30.

From relay pin 87, you want to run a thick wire to the red / yellow wire of the fan motor.

Then from the fan motor you should have a thick brown wire. This wire wants to be connected to a ground point.
Extend the wire with a thick cable if required.


Does that help?
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Yes, that's what I had in mind. I only asked since all the wiring diagrams I found on Google insisted on using a relay instead of running power straight from the switch to the fan. I suppose it will be easiest for me to just wire up a new relay, since everything is currently wired up behind the dashboard and I'm also using that wiring for my navigator. Especially if there's a switched 12V wire in the engine bay.

I suppose I expected the system to be much more complicated than what amounts to a simple temperature-activated switch and a relay. I'll have to cast a hopeful look in the engine bay to see if I can find the clipped original wires, but now I have a good plan for what to do if I can't. Big help, thanks.
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

Yes the relay acts as the high current switch.
(Contacts 30 and 87).
30 - power in.
87 - out to fan motor.

The other two wires allow a standard switch to operate the relay.
Pins 86 and 85.
86 - low ampage switched power supply.
85 - earth for relay.

Simples.
The whole circuit is rated 30 amps, so I allow a safety margin and use a 40 amp standard 4 pin relay.

The control switch can be a standard dash switch or your thermo switch.
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Well, hell. Look what I found tucked away behind the radiator...

Image

Things just got a lot easier.
The switch has three wires, and the loom coming off it has two connectors. One has a brown and black wire, the other has yellow(+white? Can't tell), black and brown. I trust the fan hooks up to one of these? Parts store guy said the switch has two speed settings. I've got connectors for these laying around, now I just need to know which wire goes where and we should be golden if the switch itself is fine.
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Disregard my last! I've found the original clipped wires near the battery and twisted them back together. Bit late to idle my car for ten minutes, I'll have to check if the fan works tomorrow. I found an intact 10A fuse for the fan in the fuse box, I'm hoping someone just didn't know the proper value, assumed the system was broken for blowing fuses and clipped the wires. More likely my brother didn't want to shell out the 20 euro for a new temperature switch, but we'll see tomorrow. I'll have to give him a call and ask.
If I'm lucky, I'll have a proper fan again with just a dab of solder and heat shrink!
Call them Cavs, but mine's a Veccy. <3
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

Here's to hoping it is a simple fix :thumb
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

No dice. Went around town, got it up to 95 degrees, no response. I did the jumper lead test on the switch plug, and the fan did spin, but only on one speed. I suppose the switch is faulty, but how will I get both speeds working?
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Re: How to rebuild the radiator fan switching system + Loud

Post by Robsey »

I am wondering if it is just Opel being odd by fitting a three pin switch when it is not needed. Unless it is a mainland Euro specification.

If you had air con, then I believe that the radiator fan always runs at the lower speed when air con is switched on, due to the extra effort on the engine to run the compressor.

According to haynes, the brown / white is the full speed supply from the relay.
The brown is to ground.

The other wire goes to a mystery connector X86. (??).
But as said - this connector is not explained and so is a mystery.

If you have the two speed fan, you should have the fuse / relay box at the rear of the engine bay. The fan fuses and relays should be in this engine bay fuse box.

Basic single speed fan systems have a fuse in the main dash panel fuse box.
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Re: How to rebuild the radiator fan switching system + Loud

Post by VectraGoVroom »

Always a possibility with these cars. No fuse box in the engine bay. I read something about there being a plug in the engine bay near the battery where one can plug a fan resistor and unlock the dual speed functionality. If I find that in there, I'll be tempted to try out one of those 100W resistors you can get on eBay for a few quid and see what happens...

"Cavalier and Calibra.
Many of these are allready wired for 2 stage so it's very easy to upgrade.
All you need to do is change the fan switch for the 3 pin switch and screw the resistor in to the holes provided infront of the battery tray. The resistor plugs into a 2 pin connector by the battery with thick brown/white and brown/yellow wires. Not all cars have this wiring but most do."
Call them Cavs, but mine's a Veccy. <3
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