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Discussion Starter #1
I was replacing my condenser today and saw the following. I guess this is why the radiator fan did not work when I first purchased the vehicle.
 

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So does it work now?
 

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Discussion Starter #3 (Edited)
When I bought the car years ago I went the cheap and easy route and bypassed the switch and low/hi speed resistors with an adjustable switch with a sensor in the radiator matrix that turns the fan on high.

The plan now is to replace the condenser O rings with buna o rings, replace the receiver/drier, replace the switch, and remove the adjustable switch to see if the fan will work as it was designed.
 

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Here's something I came across a day or so ago, while looking for a schematic to build one of these. At this price, and free shipping, I think this may be a deal!

10 50V 40A DC Motor Speed Control PWM HHO RC Controller 12V 24V 48V 2000W Max | eBay

I have one on order to try. I'm thinking of this to replace the resistor for medium speed control of the fan while using AC.

Can someone advise me where to take the input from so that it doesn't cycle on and off with the compressor clutch? I'd rather have it come on and stay on when the "Econ" switch is used

Look at their ebay shop where other units are offered.
 

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I don't quite understand what you want to use this for, Dennis. When you select "ECON", the compressor clutch doesn't activate, but I'm sure you know that. I just don't understand the advantage of this unit.
 

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I'm puzzled as well, since the resister pack for the hvac system works pretty well, varying the fan speed according to the programing for the system, or you can manually change the hvac fan speed as well, a/c off and on. I do both on occasion.
 

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Ohhh, maybe he's talking about the heater blower fan, not the rad fan:)
So probably the heat sink fan controller failed. The one attached to the evaporator housing. I had one of those fail on the Hit&Run. One of these speed controllers would have been nice for that.
 

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Seems like it would be easier to just get another original one, as I think they rarely fail, and should be plenty of inexpensive used ones laying around. That way, one wouldn't have to fiddle with a unique setup.
 

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I have been running an aftermarket radiator fan for a few years, without the resistor, so it goes to high speed right away. I also have a fan controller that uses a probe in the radiator fins, set to turn on the fan at about 185 degrees. NO resistor.

The same controller turns the radiator fan on at full speed when the A/C is running - which we do by turning the "Econ" function off. It does this by sensing voltage on the A/C compressor clutch.

My hope is to turn the radiator fan on at a lower speed when A/C is in use, and to keep it running, rather than to have it turn on and off with the A/C clutch. I've looked at the wiring schematic, trying to find a connection more directly to the Econ button, but so far it is eluding me.

So that's why I asked the question........

As for the PWM fan controller, these control DC (fan) motor speed by applying voltage in pulses, rather than changing the supply voltage by introducing a resistor. Speed can be set manually, on the controller. There are other controllers that sense temperature, as an example, and vary fan speed accordingly, which would be nice, but they are very expensive, more than I'm willing to spend.

This whole plan is due to being house-bound by high outside temps and humidity, it may go away when Fall comes to Kansas.
 

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Go down to the local parts store and replace the OEM unit with one from a 88 VW Golf 1.8L. Wahler MFR#: W0133-1631049

The VW unit has slightly lower trip temperatures and you will need to crimp-on some male space terminals.
 

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John, Thanks for your answer. Years ago, I hit a deer on the way home. One of the things damaged was the radiator, so I had it rebuilt with a new core and brass end tanks, and it has served me well. I also bought a new aftermarket fan.....

There was no provision made for a coolant sensor of any kind, which is why I have the probe-type temperature control.

Hope this helps.

I'll do some more research to find the source of voltage after the "econ" switch is set for A/C.
 

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My hope is to turn the radiator fan on at a lower speed when A/C is in use, and to keep it running, rather than to have it turn on and off with the A/C clutch. I've looked at the wiring schematic, trying to find a connection more directly to the Econ button, but so far it is eluding me.
Not making any sense to me? :blink:

Fan comes on with the compressor, but you want the fan to come on with the compressor? These compressors don't "cycle," either A/C is on or off. Maybe I'm reading that wrong.

I have my 240 Volvo set up with a relay so that when the A/C (compressor) is on, the condenser fan is running. Pretty simple to do only problem is, when I'm driving down the freeway I don't really need it to do that. Just haven't gone back to rethink how I have it set up. I guess I just need a manual switch added to turn it off for highway travel. One day I will go in and add a switch to disconnect the ground to the relay for the manual override on that setup.
Charles
 

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The fan doesn't necessarily come on with the compressor. It is commanded on by the trinary switch on the receiver/drier when the high side pressure gets to about 220 psi and shuts off as the pressure drops to about 160 psi.

Of course, when the car is in forward motion with airflow over the condenser, the high side pressure will probably not get to 220 psi, and therefor the fan will not come on.

The OEM radiator fan system is pretty well thought out and I don't see the value in heavily modifying the operating principle of it. In fact having the fan on with the car at speed, I would think that a detriment.
 

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In the case of the '89 240, it never had a condenser fan from the factory and the dryer only has a pressure switch, so I had to improvise a down and dirty way of getting the fan working with the A/C. I really do need to go back and study the wiring of a model that came with the fan from the factory and recreate that circuit.

I agree on the 164, it works well as it was designed and the best thing to do would be to keep it original, however Dennis has a unique radiator now. I think though that I would try to use an aftermarket two speed fan switch that fits in the fins and see if that could work with the rest of the OEM system.
Charles
 

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Thanks guys, I think I have found a solution to work with. I should have left things original, but I didn't so now I will work things out and maybe even get it better.

On to better things.
 
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