GQ (RB30) A/C Thermo Fan

Gday all,

Seems like a lot of folk have trouble with that little fan near the radiator, that's meant to run while your A/C is on. I've trawled a few forums but couldn't find a complete answer to this, apologies if it has been covered elsewhere.

I've never seen my fan working or turning on. A/C has just been overhauled and works fine. Have been tracing wires...

On the relay: The fan can get power from the red/blue wires, and shorted together powers the fan up no worries. The orange wire runs to the compressor. Not sure where the blue wire runs. So either the relay is stuffed (which I will check), or problem is the orange or blue wires.

Couldn't find a wiring diagram for A/C showing the thermo fan. (1990 GQ RB30)

Cheers fellas!

Attachment 74572Attachment 74573

Interesting I had a quick look at the factory manual download, but Page 12-28 of the Haynes download is the only diagram I can find that mentions a condensor fan. 12-30 has an aspirator fan.

It looks as if the fan only comes on when the thermo switch or AC pressure switch are activated. It seems wrong that the White red is powered at all times, because the solenoid would be on, even if the vehicle is off. Unless it is only on when the ignition is on, but that is not what it shows.

Quote:

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Originally Posted by mudnut

It seems wrong that the White red is powered at all times, because the solenoid would be on, even if the vehicle is off. Unless it is only on when the ignition is on, but that is not what it shows.

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My wiring colours are different but yeah White/red is straight onto the battery e.g. always hot. Still can't see the connection between the Compressor/FICD solenoid PPL wire and the relay (this PPL wire goes directly to the condenser fan relay on my GQ, which could be what switches it).

Will have a play around and report back!

You have checked the 10 amp fuse, Yes?

The fan should run if the A/C is on OR the coolant temp rises above approx 102 Deg even if the A/C is off.

...and AFAIK none of those wires should be hot off the Battery (but the piccy doesn't show the source of the Wht/Red and my memory sure isn't that good)

Quote:

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Originally Posted by the evil twin

The fan should run if the A/C is on OR the coolant temp rises above approx 102 Deg even if the A/C is off.

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Thanks good to know that!
Sounds like a condenser fan on 1990 GQ could be a dealer, not factory, modification hence non-stock-looking placement of the relay.

I think the fan activation on due to coolant temperature may be only an Auto thing...? E.g. only Auto's had the thermo switch?
Attachment 74577

That doesn't make sense to have the coil of the relay dragging amps all the time, does it? Page EL 6 of the factory manual shows the brown link for the A/C and it is alive while the battery is connected.

POST EDITED.

The Manual and Auto Tranny Rads are different.

The "Thermo Switch" is a sensor on the lower RH side of both the Manual or Auto Rads

The "Thermo Switch A/T" is a sensor on the lower LH side of the Auto Tranny Rad only

I was wrong about the power as I thought it came from one of the A/C interlocks but it appears it is indeed hot (been too many years since I had a GQ I guess).

I have found a few differences in the wiring from the after market diagrams so we'll just have to nut this out. It seems counter productive to run a relay all the time. It would drain the battery, wouldn't it? .

Quote:

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Originally Posted by mudnut

I have found a few differences in the wiring from the after market diagrams so we'll just have to nut this out. It seems counter productive to run a relay all the time. It would drain the battery, wouldn't it? .

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Yeah, seems a bit odd to me but its ages since I put a manual override for the eleccy fan in a 'Q.

I've done a few GU's lately and are totally different as teh Fan Control runs of the A/C interlock so is only powered in "Ign On"

I would switch the White/red with the blue wire in the above diagram. That way the the condenser fan relay only operates and switches the fan an on when either the thermo switch or the pressure switch activate. The only problem I can see with that is it relies on the fusible link to blow,if there is a short.

Hey fellas.

Spent a few hours on this over the weekend with the multimeter. Completely did my head in!

The 2 wires (+, earth) coming out of the fan EACH had connection to battery +'ve AND earth with engine/AC on. E.g. the multimeter beeped on both battery poles on either wire. The fan didn't work (obviously...?!).

Not sure what's going on apart from a short somewhere. Will post again once I've sketched out my own diagram, or given up and hard wired the thing to run with the compressor!

Cheers.