allittle backstory...

last weekend i had replaced the crankshaft position sensor o-ring, vapor syliniod, repaired/installed power steering cooling fan(PSCF), and left inner cv boot.

turned the car on, no ses lights, went to check the PSCF and it wasn't moving. so i remember reading that the PSCF circuit is part of the radiator cooling fan(RCF), so i check to see if the RCF was moving and it wasn't. so i took the car around the block (it only takes a few blocks for the car to get to temp, is that normal) until it got the temp guage to midrange, went home, poped the hood, and the RCF still wasn't moving. next i saw that F1-F4 were identical, moved the relays around, and the fan still didn't work.

so i took the fan out, since its a known issue, noticed i had the 2 plug version w/relay, took it to work, and we were able to test it out. the fan works great for low and high speed, relay switches just fine. ohms and funtional tests great.

so the question is, " what am i missing or where should i look next"

on a side note, i did turn on the a/c and set to low, still nothing, besides the fact that it seems the compressor didn't engage either because its low on stuff or the clutch coil is shot, i dunno, thats for next time...

 

What year car....
On pre-2005 unmodified PRODUCTION cars, there is 5 amp fuse that both thev ps fan and the radiator fan share...forget thee fuse number...just check them all!! About a 2 minute job with a multimeter.....

 

2003 r53...

under the hood or in the car?

 

checked a 30 and 50 amp fuse under the hood. checked good. fan still doesn't work

 

Five amp..
Not fifty...
When the PS fan siezes....the 5 amp (provides power to a relay needed to turn on the radiator fan) blows....so no fans...my car was delived this way...then rewired by the dealer under a service campaign....
Very common issue. I forget which fuse cause it has been since spring of 2005, but it is a 10 second fix...if the PS fan is not siezed.. If it is...will happen within minutes.
This is s very common issue on pre 2005 production cars....do a search.

 

alright, so I checked evry fuse, all good.


ran the car awhile with the ac on, and finally the high speed came on, but no low. seems like its the radiator fan assembly, but it checked good outa the car, so idunno anymore...

 

is there a thermocoupler that tells the fan to turn on?

 

does the low speed start as soon as you turn on the car?

 

You really need to use the serch ....
You diagnosed it wrong...sent yourself on a wild goose chase...
If you have an odb2 reader with a guage feature, you can monitor water temps and compare the fan turn on to the exact specs it turns on...posted in about 90 threads....
High is the last ditch before car overhreats....low should have been on before...
Fan only runs when the car needs it..hmm...based on water temp or the ac pressure switch telling it to turn on...a trick to turn it on at lower temps....

 

PS..
Radiator temp guage on all but the 2005+ chrono pack cars is a dummy guage...
Is in the middle once car is "warmed up" stays there till moments before it overheats...no real info...just car is "warmer" than ice cold.

 

So did you find out a solution?

 

Actually the chrono gauge moves right along with the temp my scangauge shows, I can pretty much tell when it's going to come on by the chrono needle, you can even see it start to drop as the fan is working. It's just not linear, quick down low then slower at operating temperature. So the movements are pretty small. I think from 198-222 the needle moves like 2 needle widths.

Low speed fan comes on at 222°F.
High speed comes on at 235°F.