Yeah, it had 2 codes; P0128 and P1258. I initially checked the codes, cleared them with my actron:cp9575 code reader, started the car and watched live data on the temp sensor go from 180 to 228 F - that took 15 to 25 minutes with the hood up. No low speed or high speed fan at any temp. 2 hours later and car cooled down I turned on the separate AC button at 195-198F the left fan(Passenger side) ran on high for a only a few minutes then went into low speed, while the right fan(driver side) ran slower never high, after seeing your schematic it looks like there must be a dual windings on 1 fan motor(for 2 speed operation) while the other fan is a single speed. After a long time to get the temp up to 228-230F only both fans ran on low speed, never got a hi speed again. Shut down the car and let cool. All 3 fan relays check fine with hot wired the coils and ohmed the contacts, ohms seemed good not like dirty contacts and high ohm reading. So the fact that I got temperature in Fahrenheit from the PCM on my scanner should seem to tell me the temp switch/sensor was talking to the PCM. I got a 40 step instructions from a buddy off Alldata but I need a scan tool to now go further.I couldn't find the diagram on this lacrosse only other Buick which I could see were not the proper ones for this car, so thank you for that now I gotta see if there is any way without the scan tool to use a meter, test lite, jumpers, etc to keep going. I wonder if the pcm ground is it's metal housing and a corroded bolt, or gonna be a separate wire/group of wires under the dash or in the engine compartment to see if it's a ground issue, other wise it's going to be the darn PCM? Okay, where's the PCM at? Lol. Dash or engine bay?
Friday, April 17th, 2020 AT 5:50 PM
