|05-14-2014 04:58 PM|
Jumping the low speed fan won't do anything if the resistor is blown, as the resistor is in the positive lead to the fan.
It's been a long time since electronics, but the bottom line is that Wattage is more about heat dissipation.
Resistor Power Rating and the Power of Resistors
|05-14-2014 02:07 PM|
the plot thickens:
If I jump the relays, the fan spins at high speed, but not at low. That makes it pretty clear that the fan motor is fine.
Jerry from Sweet Motors confirmed that my fan would be 330 watts, since it is a two speed fan.
What he found odd is that the resistor wattage value should be between 50 and 75 watts, as reported above, with a 300 watt load.
I am not an electrician, so if anyone can shed light on this, I would love to understand it.
|05-13-2014 04:41 AM|
|g96nt||Id check the fuse, but if I had to replace the unit, I'd buy a nice low-mile replacement from the junkyard and replace the resistor before I installed it. Do it soon, because it won't be long before you pop radiator hoses...or the radiator|
|05-13-2014 02:30 AM|
the part I listed above is NOT the correct part. I ended up ordering this digi-key part:
I have not installed it yet, but now I have a new challenge. The fan no longer runs even at high speed, which means that the fan motor may have gotten tired of being run constantly as a result of leaving the a/c on, and has quit.
I am now looking at fan motors and assemblies, and I see that there are several values for the wattage rating. How do I find out whether I have a 250 or 330 watt, are they interchangeable, and if so, am I better off with the higher wattage unit ?
|05-01-2014 06:57 PM|
Okay, everybody. Back from my visit to Sweet Motors in Mt. Arlington NJ, and have I got a story.
Please read my thread titled "local help", where I will post about this visit in detail, but Jerry Sweet, of Sweet Motors, is not only the most competent mechanic I have met, he's a really nice guy to boot.
I was ready to replace both the thermostat and coolant sensor, but he didn't want to do that, and said that the problem was not there.
He quickly and effectively found the source of the issue.
The DICE in my car was programmed for a single speed fan, while my car is actually a two speed fan version. He fixed the programming, and then it became clear that the low speed fan was not working.
I found the part here:
I found that a little pricey, and Jerry said that he would cut one out of another car for me if he can, which means that I won't pay much for it, and he won't even get to do the work, which I told him I would do. Where do you find a guy like that ?
Interestingly, although he is pretty much a Saab shop, he told me that he has only replaced one of these resistors in years of work.
Thanks to everyone for their help.
|04-30-2014 06:27 PM|
I was off. it's .2ohm and much higher wattage.
here's a how-to.
NG 900/9-3 Fan Resistor Replacement - The Saab Tech Wiki
|04-30-2014 06:23 PM|
I used to know offhand. It's nothing crazy 20 ohm 10w, maybe? If yours is blown, it'll show infinite resistance, the fan would work with almost anything else.
And the a/c can be on with heat or cold.
|04-30-2014 06:17 PM|
thank you for the replies.
I will look for the resistor. Do you know the value it should be ? I do have a multimeter to check that with, and unless there is something special about it (other than having a Saab logo), I can get another one.
I don't have a bus reader, but I suppose my mechanic does.
I'm going to take a wild guess that the sensor is a dealer part. Can that be gotten cheaper elsewhere ?
This is not the best weather for keeping the AC on, but hopefully that will soon change.
|04-30-2014 12:09 PM|
As stated, 9-3 have a goofy fan setup. It's a single fan, and when the low fan is needed(80*c-100*c), the "ECU" sends 12v through a resistor, which drops voltage, and spins the fan slowly... when the car sees 100*+, it sends full voltage straight to the fan, so it spins much faster(think: emergency mode, or high load)
The problem is, the resistor is exposed to elements, and heat from the turbo. Eventually it pops(like a fuse) the result is an incomplete circuit to the fan when the ECU wants it on low, and the fan doesn't work. The coolant temp creeps up, and by the time the ECU sees the 100*, it's already too late. You've built a ton of pressure, hoses pop, or the pressure valve under the reservoir cap pops, and coolant spills.
The temporary fix, until you can solder another resister in, is to keep the A/C on.
when the a/c is on. the ECU turns on the high fan for 30-60 seconds every other minute or so, regardless of heat, which will keep you from overheating.
|04-30-2014 11:26 AM|
|Drew in Houston||
If your hoses are hot, then it sounds like a potential cooling fan issue.
-let it get hot and plug in a bus reader to check that cooling temp sensor is reading a believable temperature. Sometimes they go bad and report a temperature that's too low, so the fan never activates. If you're boiling out coolant and the bus temp reads below 100C then the sensor's probably bad.
-check to see if the fan ever turns on. Turning on the AC should make the fan turn on much more frequently.
-check to see if your car is the 2 speed fan version or 1 speed. 2 speed versions have a resistor mounted on the fan body by the fan motor, and those resistors go bad.
It could be other stuff, but those are easy/common failures to check first
|04-30-2014 09:38 AM|
My newly acquired 2001 9-3 has twice done something to concern me.
After a highway drive of about a half hour, without pushing it at all (turbo needle never goes into second section), I drive at local speed for maybe ten minutes, and when I stop the car I get white steam from under the hood, and a puddle of antifreeze. The expansion tank is just about empty, but I only have to refill the tank itself before the fluid comes up to the top, and the system was pressure checked, so no bad hoses. Yesterday, when it happened again, I opened the hood in time to see that it was spraying out from under the yellow cap of the expansion tank.
I imagine that if the cap were bad, I would be seeing the problem every time the car heats up, which is not happening. Anybody with a clue ?