I have a 2019 Ford Escape. I bought it as a rebuilt. Normally the radiator fan runs about 10 seconds when the car turns on. Then it appears to never come back on again. I have replace relays, ambient temperature sensor, and radiator fan. Even when turning on the A/C the fan will not turn back on again. If I jump the relay for the both low speed fan and the high they run just fine. Then when I put the relays back in and turn off the car and back on again the fan comes on when turning on the A/C. Even when doing this several times. Then sometime later the fan just starts only working again for the initial 10 secs. I have tried wiggling wires along the path when the fan is running and they keep working. There has been several times the car was almost overheating and I had to stop and turn off the engine and wait awhile before I could drive it again. I took it to a mechanic who hooked it up to a computer and sent a signal to turn on the fans and they didn’t respond. What can the problem be?
A rebuilt tittle typically means that the cost of repairs was about 75% of the worth of the vehicle, normally from a wreck.. The rebuilder could have/probably used mainly salvage yard parts and may not be the correct year for the vehicle, meaning mix matched parts… Could also have a pinched wire(s) from a body panel being replaced… You may find a simple solution to this or it could be a complete nightmare and money pit trying to find the issue…
From most of the rebuilt tittles I have run across over the years, I wouldn’t wish them on any mechanic.. You might have to take this to a specialty automotive electrical shop and hope the repairs don’t exceed the worth of the vehicle…
Sorry you are dealing with this and good luck…
The fans are driven off a command from the ECU. The statement above tells you the problem is that command wire is no longer connected to the relay.
Time to get out the wiring diagrams for the car and start tracing the wires from the ECU to the fan relays to determine the disconnect. This takes time - a little or a LOT. Be prepared to pay your mechanic a significant sum.
Today’s engines are easily damaged by overheating. You really want to solve this as quickly as possible.
Thanks, for all of the comments. I will start by tracing the control wire for the fan calls myself. I already put $1500 into this vehicle since I bought it in the winter (live in MI) and couldn’t check that the air worked. (It needed a new compressor etc.)
If it is the the control wire not sending the signal since it is pinched or broken how does turning the air on start the fans after I jump it and put the relay back in and restart the car?
Looking at the wiring diagram, the relay controller for the fans in the ECU may be failing.
Tester
There has to be a sensor somewnere. If there weren’t one the computer couldn’t even guess the temp. Used to be you would find and replace the cheap thing and go from there.
There are a couple ways to approach this. The best is to have access to this tool, a multimeter and a schematic. Command the fans on and start at the ECM/ECU/BCM or whatever is driving the fan control and see if the output of the module matches the control signal (could be grounding or supplying power). Then follow it to the fans until you find the signal loss…
The other approach involves guessing and replacing the most likely culprits. Since they actually run for some brief period at times, that guessing game could end up being expensive (i.e. probably not the fan relay(s)).
Sounds like you need a better mechanic.
I would assume the car still has an old fashioned water thermostat. So maybe just wire up the fan to run always?
If the problem is a broken or damaged wire, or loose electrical connection/cracked solder joint in the fuse/relay box, I would locate and fix it (or replace the fuse/relay box if it’s unrepairable). If the problem really is the PCM, I would not attempt to replace the PCM. I would find a circuit which is energized when the key is in “ACC” or “ON” and tap into that to power the coil of a relay (NOT the actual fan) and connect one of the load terminals directly to the positive battery terminal (making sure to put an appropriate fuse and fuseholder as close to the battery as possible), and connect the other load terminal directly to the fan high speed. This will allow the fan to run whenever the vehicle is in use, so you don’t ruin the engine, and the fan will turn off when the vehicle is not in use, so you don’t drain the battery.
Edit: Here is an example of the type of relay to use, which includes a waterproof socket with pigtail leads. Note that this is just posted as an example, and I am not connected to Amazon or this seller in any way, and I don’t necessarily recommend this brand.