Hello everyone! Radiator fan issue

[Focuslu86]

the car doesnt overheat all the time, when i drive it its fine! it overheats when i am stuck in traffic and as soon as i hit the gas and go, the temp gauge goes back to normal!

[Lscman]

Originally Posted by Focuslu86

the car doesnt overheat all the time, when i drive it its fine! it overheats when i am stuck in traffic and as soon as i hit the gas and go, the temp gauge goes back to normal!

This is true with most cars. They will operate OK about 90% of the time without symptoms with no fans. The thermostat is running wide open and trying hard to maintain proper coolant temps with inadequate air flow. It's the other 10% of the time that leads to engine and A/C system failures where the caqr is moving under 30 MPH, sitting at stoplight or running in traffic with poor air flow. Are you lucky? Russian roulette doesn't always lead to death, but that's no reason to play. Any time the temp is temporarily above normal the head gasket and aluminum engine is being tortured. You are taking life out of your motor when driving it with no fans. Actually the other part of your car that you are torturing is your radiator. It has plastic tanks with synthetic seals that can't take that heat for long. Without fans the hot soak issues and elevated pressures are abusing your radiator, hoses and heater core.

[Focuslu86]

Thanks! So best thing i can do is take it to a shop and tell them to check my cooling system, radiator fans, etc! Can i check the relays before i take it? I mean i have the tools needed to test if its working or not, just wanna know if anybody can explain me how i can test this issues using a multimeter or a master probe test....

[Lscman]

Originally Posted by Focuslu86

Thanks! So best thing i can do is take it to a shop and tell them to check my cooling system, radiator fans, etc! Can i check the relays before i take it? I mean i have the tools needed to test if its working or not, just wanna know if anybody can explain me how i can test this issues using a multimeter or a master probe test....

Based upon the symptoms you described, you have not yet destroyed the coolant system or engine so they don't need checked. You just need to get the fan circuit immediately repaired.

I'm an Electrical Engineer with plenty of troubleshooting experience, but I can't help much. This is because I can't work blind. I don't have a Focus 2001 wiring diagrams and Service Manual. Even if I did, I would still need to know precisely what car options you have to determine which wiring diagam applies. The other issue I have is engine control computer or ECU basically control the fan relays. This stuff is not covered by wiring diagrams. It takes some investigation, some sections in the service manual would describe that. This is why both pieces of factory literature are needed. What can be done with the wiring diagram alone is the relays, wiring, resistor pack (if equipped) and each fan can traced and tested for possible open ckt or grounding. In some cases, dual fan relays can actually be swapped to see if the problem moves but that only works on some cars with specific options.

If I were you, I'd be taking it to a dealer for this trouble while buying literature to have handy for future issues.

[Focuslu86]

Originally Posted by Lscman

Based upon the symptoms you described, you have not yet destroyed the coolant system or engine so they don't need checked. You just need to get the fan circuit immediately repaired.

I'm an Electrical Engineer with plenty of troubleshooting experience, but I can't help much. This is because I can't work blind. I don't have a Focus 2001 wiring diagrams and Service Manual. Even if I did, I would still need to know precisely what car options you have to determine which wiring diagam applies. The other issue I have is engine control computer or ECU basically control the fan relays. This stuff is not covered by wiring diagrams. It takes some investigation, some sections in the service manual would describe that. This is why both pieces of factory literature are needed. What can be done with the wiring diagram alone is the relays, wiring, resistor pack (if equipped) and each fan can traced and tested for possible open ckt or grounding. In some cases, dual fan relays can actually be swapped to see if the problem moves but that only works on some cars with specific options.

If I were you, I'd be taking it to a dealer for this trouble while buying literature to have handy for future issues.

Well, I am taking my car to the shop on friday, but not to the dealership since they are going to charge me an overpriced amount to fix that...I have already bought a wiring diagram for my ford focus 2 days ago, so it should be on its way! can any repair shop can diagnose what's the problem? or it has to be a specific ford dealership to fix that?

[amc49]

You must get out of car and check whether fans (both) are actually working when the overheat occurs, they MUST. Or you can pay someone else to do that, so many don't even want to exert the effort. If fans not working then check the fan resistor which is in the top middle of the radiator fan shroud, two wires running to it, unplug and see if melted there, very common on these. If so you need the resistor and possibly the plug connector as it often melts too. Fix yourself and save the easiest $100 bill you will ever make.

[Focuslu86]

can a bad head temperature sensor cause the radiator fans not to work? i have checked relays, fuses, resistor, wires, pigtails, ect. but i havent checked that sensor...can that be the problem?

[Lscman]

Originally Posted by Focuslu86

Well, I am taking my car to the shop on friday, but not to the dealership since they are going to charge me an overpriced amount to fix that...I have already bought a wiring diagram for my ford focus 2 days ago, so it should be on its way! can any repair shop can diagnose what's the problem? or it has to be a specific ford dealership to fix that?

Ford techs have seen the same problems hundreds of times, so they can fix this stuff with eyes shut. Independent will be working cold without as much expereicne on that model, so it takes much longer with spotty results. I would not use indy for such electrical work. they are better used for mechanical work or stuff that can be diagnosed thru code readers. The electrical troubleshooting procedures are in the service manual, not the wiring diagram book.

[Focuslu86]

So when i pay them, i have to close my eyes and give them my wallet hahahah! i will find the source using the ect2000 and the master probe 3... Has anybody used those tools before?

[tmittelstaedt]

I fix computer networks for a living and only do car repairs as a hobby - I must echo what others are saying - unless you have a couple weeks you can park this vehicle that you can learn electrical troubleshooting on, and following a wiring diagram - your asking for trouble.

If you simply don't have the money at all then go to a wrecker and cut the fan plug off an existing fan harness, unplug the fans on your car, plug in the wrecking fan plug and wire it directly to the battery with a switch, you can run the wires into the passenger compartment for the switch. then manually turn the fan on when you start the car and turn it off when you stop. Hopefully your diagram will show + and - on the fan.

It will probably reduce your gas mileage with the parasitic drain but it will keep the car engine from melting down while you screw around with it.

You need more than the wiring diagram you also need the diagrams that say where the wires are located in the engine compartment and what harnesses they are run inside of. Hopefully your wiring diagram you bought includes that.

I am very familiar with troubleshooting automotive wiring from a tech manual and going in cold this would be at least a 2-3 hour job for me if it wasn't the fan resistor (which of course I would check first). If I was a mechanic doing these all day long in a dealership it would be a 20 minute job because I would know exactly where all the failure points are. And yes I know that if it does take the mechanic 20 minutes to find it your still going to be charged book time of an hour or two or whatever it is - that is how service departments make money - it may seem unfair - but they do have to warranty their work and it is not uncommon for electrical problem fixes like this to fail again.

Most of the time when I've done these things if it's not an easy fix (like the resistor) I end up starting off by following all wiring carefully - about half the time the wiring is chafed, or melted on a header or some such, and even if you know a particular circuit segment is dead by testing with a multimeter, it still takes ages to find the physical wire and follow it through from the diagram.