volvo fan installed. now what?

[n2motorsports]

Finally gave up on running both fans so I went the easy route and used the aux harness to run the volvo fan. 

Here's the problem the fan doesn't turn on unless I hit the ac button. Is that how you guys are running it?  At freeway speeds its not a problem but city driving I have to hit that switch at all lights.  Btw my temp gauge crapped out so I can't tell what temps im running.   So the question is.. does your volvo fan kick in automatically?  Does your fan turn off automatically once the temps go down?  Other notes.  I swapped the temp sensor to the new one and replaced fuse #3 to a 25 amp.

Thanks.

[DesktopDave]

Test the tempstat switch on the radiator by shorting either black wire to the brown ground wire.  One brown wire is high-speed, the other is low-speed.  It should definitely do that automatically.  I put a tempstat that was rated too high so my fan doesn't work automatically either.

[IlovM42]

you can put an E36 temp switch that are rated lower than E30 ones

[ti_tony]

The circuit is funky for the cooling fan. Check the temp switch like was menitioned and if thats OK change out the Hi speed relay. It's the megenta [I'm color blind, kinda purparlish color] one that BMW used on many different models. Also check the yellow low speed relay. I went to Pull a Part and got a couple spares, they are about $45.00 otherwise.   

[monty23psk]

Search for my topics on this as I have dealt with every possible thing regarding the Aux fan. If the AC button turns it on, then you low speed relay is fine, your resistor is fine and your aux fan is fine. If it does not turn on when the engine temp goes up, either the temp is not registering correctly on your gauge, which could be sensor or gauge and you think it is hotter than it really is,  or your radiator temp switch is not kicking it on. I would, as suggested above me, test the aux fan at the radiator temp switch to make sure fan turns on at low and high. If the switch might not work on low but should also on high. Test and you will see where the issue is with the temp switch. Also, if you are depending on the fan to turn on to cool the engine, and your car is not in very heavy stop and go traffic while it is over 80 degrees outside, your m42 is having issues with the coolant system and you need to get that fixed first.  If you need to replace the rad. temp switch, get the e36 lower degree version so the volvo fan turns on sooner.

[n2motorsports]

Thanks everyone that's inputted.   I did all those test and everything worked as it should then itt dawned on me that I never really bleed the system.   So I go find a hill and pour 1/3 a gallon of distilled water in there and now the fan kicks in automatically!  Damn air bubbles!  Now im moving on to the 1223 error and temp gauge problem.