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Old Sat 13th May 2017, 01:13 PM
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MY EA81 radiator cooling fans

Anyone have any knowledge on the wiring and purpose of the radiator cooling fans on an EA81 fitted with A/C and twin electric fans.
The twin electric radiator cooling fans in my 82 model EA81 Touring wagon and not switching on when the coolant temp gets high preferring to blow coolant everywhere instead (via the overflow bottle).
I see on the firewall side of the inlet manifold 2 x temp switches are fitted.

As per the following photo (switches circled in red) I think the one on the right drives the temp gauge on the dash but I don't know what the other one does.

If anyone has any schematics for the fan system it would be appreciated and/or other info.

I think one of the cooling fans only comes on when the A/C comes on but I dont know if this same fan comes on when the temp rises.
Would also like to know which relay(s) may control the fans and where these are located in the car.
Any advice appreciated.

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Old Sat 13th May 2017, 02:35 PM
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The sensor on the left of your pic usually tells the manual choke to turn off, if you have manual choke.

As for A/C wiring, the relays on the drivers side strut tower do all the work (if you have a "factory fitted" system) There's a few different systems as far as I know. In my manuals schematic it looks like the main radiator fan only comes on with the thermo switch in the radiator. The condenser fan should turn on with the A/C button in the dash and stay on as long as the A/C compressor is running (so it cycles on and off with the evaporator temperature sensor) The weirdest thing I found with the system in my manual was that the condenser fan turns off if you turn the headlights on

If your main fan isn't coming on I would suspect the thermo switch in the radiator. If your condenser fan isn't coming on with the A/C button it could be many things. I would look at fuses first - the A/C fuses are separately mounted glass tube holders in the wiring, not integral to the fuse box. I think there's one by the battery and one under the dash near the fuse box. Next I would suspect the relay(s) on the strut tower, being 30 years old they could be at the end of their useful life.

Hope this helps, I'll try and get a decent photocopy of the wiring diagram out of my manual. It's hard though because the book is so thick I can't get the whole page on the scanner
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Old Sat 13th May 2017, 04:15 PM
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Silverbullet.

Your the man !!!!

From your info re the radiator thermo switch turning the main radiator fan on I thought that the thermo switch should be a normally open type and when it gets to temp the contacts close sending the circuit to earth so turning the fan on.
Note - I replaced the radiator thermo switch a year or two ago.

I pulled the switch wiring, started the car and used a jumper wire from the switch wiring plug to the chassis.

This caused the main radiator fan to come on AND the A/C fan too.

Now, the A/C circuit is a different kettle of fish in my case as the last time the A/C worked was when we found out we were having our first 2 kids.
They will be 15 in July so it has been a "couple of years" since the A/C actually worked.
I have never opened the A/C system up so I am hoping it is still basically OK though I appreciate things like O-Rings will be shot but hopefully there is still some gas in the system keeping things sealed.
The condenser might be stuffed too as it sits in the front of the radiator and catches all sorts of particles as you drive along.
Pushing the A/C button does nothing so the gas level is well and truly below the level to get the system to work.
I have cleaned the radiator thermo switch wiring plug and plugged it back in.
When time permits will run the car and see how things go.
Might have to look into the radiator itself as I think it is the original from the car too.

Thanks for your help and if you can find any schematics it would be greatly appreciated so I can trace all of the cooling system/A/C fan system.
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Old Sat 13th May 2017, 05:02 PM
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Aha good to hear you got some joy Yep putting the thermo switch wire to ground is a good way to see if the fan still works. If you really want to test your A/C system but think there's no gas in it, you can un-plug the two wires from the pressure switch on the drier and join them together, just see if the compressor etc comes on. You could even do it with the engine off, just key in the IGN position.
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Old Sat 13th May 2017, 05:06 PM
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Thanks again, will have a look at your suggestions for the A/C test tomorrow and let you know how I go.
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Old Sat 13th May 2017, 09:00 PM
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The AC electric fan probably turns off with the headlights on under the presumption that you're driving at night when the ambient air temp is lower than daytime temps. It wod also be a way of reducing electrical load on the system.

As a safety the AC fan will most likely come on if the primary fan is not dropping the coolant temp.

Cliff, as long as you can turn the pump by hand, your AC system should be fine

Cheers

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Old Sat 13th May 2017, 10:22 PM
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Ended up getting time to pull the wires off the drier, used a lead to join them together and started the car.
Both the fans started up when the cabin fan was switched on and the A/C button pushed so all is well.
Thanks guys for all the help.
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Old Sat 13th May 2017, 11:16 PM
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Quote:
Originally Posted by El_Freddo View Post
The AC electric fan probably turns off with the headlights on under the presumption that you're driving at night when the ambient air temp is lower than daytime temps. It wod also be a way of reducing electrical load on the system.
These are the only reasons I could think of as well, leaning towards the electrical load being the main reason. They must have designed it not with Australia in mind, when it's still 30C + at night and you need the A/C you'd probably need the condenser fan too

That's good news Cliff, so your A/C system seems to be electrically fully operational, just needs a gassing you're set
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Old Sun 14th May 2017, 08:37 AM
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Quote:
Originally Posted by Silverbullet View Post
That's good news Cliff, so your A/C system seems to be electrically fully operational, just needs a gassing you're set
Probably because it hasn't been used for about 12-13 years!

Cheers

Bennie
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Old Sun 14th May 2017, 12:12 PM
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Quote:
Originally Posted by El_Freddo View Post
Probably because it hasn't been used for about 12-13 years!

Cheers

Bennie
I have been pretty slack with the A/C.
What with family stuff, moved houses, getting our old house ready for sale, car isn't a daily driver etc the years have flown.

On the plus side, yes, it hasn't had any use for 15 years.
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