1995 850 turbo.
A/C works but the condenser fan is not cycling on and off with the a/c compressor.
The fan does come on when the engine gets hot so the fan is working.
Where do I start?
Is there a relay or a fuse that I need to know about?
Driving down the highway the a/c is nice and cold (plenty of ram air to keep the a/c cool) but once you get into city traffic you might as well turn the a/c off and roll down the windows.

 

What is a condensor fan? Are you talking about the fan inside the car?

 

I think he is talking about the radiator fan...
That does not turn on with the ac.. well mine has never turned on with the a/c in 16 years.. its a cooling fan...

If your getting hot in traffic id say that your problem is somewhere in your a/c system.
Low on Freon or an over charge, air in the system, bad HP switch stuff like that.

You also have to consider your ambient temperature, flowing air is cooler than HOT rising air surrounded by running cars in the middle of a heat wave..

 

The cooling fan behind the radiator (and AC condenser) has two hot terminals; terminal 1 (red wire) is active when the engine is running hot.

The 2nd hot terminal is #2 on the fan and is activated when the AC is turned on. Both fan terminals 1 and 2 are activated by the Ignition Control Module via the Engine Cooling Fan Relay (located above the fan shroud). Terminal #3 on the fan is ground (assume that is good since the fan works for cooling).

I would suspect a problem with the Engine Cooling Fan Relay first. Locate the relay; when first start up (cold engine) you should see 12v at pin B1 (ylw/wht wire). I am betting you don't have it. If not, make sure you have 12v at pins A1 and B2. If no voltage at B1, try rapping on the relay. If that fixes it, you can take the relay apart and clean the contacts, or replace it.

If you do have 12v at B1, then try grounding pin B1; this will activate the portion of the relay used by the AC, sending power to pin 2 on the fan. If you have 12v at pin 2 on the fan, but the fan doesn't move, then the problem is in the fan itself.

 

Now that's a top notch answer!
I'm saving this post, bet it'll come in handy one of these days. Thanks!

 

Man, that IS a really good answer, gdog. Thanks. This would have been awesome for my old 850. But the 240 I'm driving now... I don't suppose anyone knows if the connections for the aux fan are the same?

I would suspect not, that it only has a ground and a temperature sensitive terminal, connected to the fan switch plugged into the radiator? But am I wrong in this?

 

Thank you, that is exactly what I was looking for.
I will check the relay and report back when I figure it out.

 

On all cars with a electric only engine fan the engine cooling fan serves 2 purposes.
1-cool the engine.
2-cool the refrigerant in the a/c system.
If there is no air moving past the a/c condenser then the a/c becomes useless because the refrigerant (R-12 in the old system's and R-134a required my law in 1995) begins to boil when it gets to hot.
Basically a a/c system works like this, the R-134a removes the heat from the passenger cabin and carries that heat to the condenser which is a radiator for high pressure gas vapor.
It then cools and the a/c compressor carries it cooled back to the passenger cabin to cool the air.
The a/c dryer removes any moisture or other contaminant from the R-134a.
The water you see dripping from under your car when the a/c on is the moisture that is being removed from the air inside the passenger cabin.
So to make sure the a/c works properly the engine fan will come on when the a/c compressor kicks in.
On some cars, like my Land Rover, the a/c condenser fans come on and stay on as soon as you turn the a/c on and they do not cycle with the a/c compressor.
My wifes car is not running hot, its just the a/c is not cold when in city traffic.
I was suspect of a relay, now I know where it is and how to check it.

 

Well it is the relay.
I took it out, unplugged it, plugged it back in and it started working but I am not going to wait and see how long it keeps working.
I will try and take it apart and clean the contacts this weekend.
If that does not work then I will source a new one.
1994-1997 Volvo 850 Turbo Cooling Fan Relay
I dont think $35 is to bad but I am going to search for it locally so I do not have to pay for shipping.
Thank you for the help guys.