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cooling fan continue to run after warmup,not cycling
I just finished a 5.3 conversion in my old ford pickup ,PSI harness and PCM,started up great runs and drives good yesterday first time on the road I gased it up and when I started it it was at temperature the fan was running but stayed on till I got back home, every thing was cool enough should have been off..before I left it was cycling fine while it was sitting in the driveway..This AM,I started it and let it warm up to temperature the fan came on and cycled like it should then the second time it came on a few minutes latter it stayed on even though the temp was pulled way down..I eliminated the relay being stuck It is completing the ground there when it shouldn't,, My guess a bad Coolant Temp Sensor?
Thanks ahead for responses
coolant sensor acts as a relay. is stuck it was pull the relay
Tramminc Im not sure if Im clear on your post.. tI think the coolant sensor completes the ground for the relay at temperature thru the PCM, while the fan was on and should of shut off I pulled the plug off the relay and checked and there was a ground activated at the plug which I believe eliminates the relay as being the problem,,
Do you have a scanner or some way to read exactly what temperature the PCM is seeing? Your gauge most likely uses a different sender and location, so they could be off some. Do you know exactly what the on/off temps are set at?
I dont have a scanner to check that just have an after market gauge with that sender in line on the upper hose and been using a laser thermometer to get a reading of things while it running "enclosed a photo out of the instruction
manual for the harness says fans set 205-195. maybe the stock thermostat is a higher temp and keeping the water in the block longer keeping the fan running? Just dont get why it didnt do it from the first start up sitting in the driveway and why this AM it cycled right the first time
Im pretty sure I got all the air out of the block but I may try just unscrewing the pulling out the sender out let some coolant run out in case there is air trapped there
Tramminc Im not sure if Im clear on your post.. tI think the coolant sensor completes the ground for the relay at temperature thru the PCM, while the fan was on and should of shut off I pulled the plug off the relay and checked and there was a ground activated at the plug which I believe eliminates the relay as being the problem,,
I just read my post, (it didn't make sense) I have to turn the auto correct off on my computer, sometimes it changes words.
01-17-2019, 06:03 PM
cooling fan continue to run after warmup,not cycling 
