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Discussion Starter #1 (Edited)
New to your forum, but not new to anything else. I have read thru threads on the search for cooling fan issues, and read thru the HOW TO section but haven't found what I'm looking for yet.

I am babysitting a 2000 Focus ZTS Zetec DOHC with an overheating problem. I have found a variety of issues that I have fixed, cracked water outlet, broken snout on thermostat housing, clogged radiator, various rotting hoses. I have replaced upper/lower rad hoses, radiator, thermostat housing, thermostat and a variety of other hoses that show signs of weakness/decomposition and leak. I have a water outlet on order since I discovered that to be leaking after I put it all back together.

The fans do not run. I can jump power to them and each one runs individually, the relays and the fuses to them are fine. I have read thru the How To and found a way to bypass the relay but am not sure that is helpful to me. In addition, since I have now taken off the broken water outlet plastic assembly, I can't really test with engine hot. When I did test, I watched the temp on the Odometer trick go up to 107C (yes, discovered that on this forum) and no fans came on. I have read about the resistor being a problem and seen numerous threads where members have been advised to change the resistor and the plug leading to it, but mine "looks" okay. [EDIT--yeah, looks okay until you disconnect the terminals....they're fried] I haven't seen a thread on how to check this otherwise and don't have a habit of just throwing parts at a problem.

I have posted up (prolly on the wrong page of the forum) an inquiry on the GEN 1 Focus page, but after 10 hours I don't even see my post showing up. Since I do not own this car I don't have the FSM to it so can't trace out the circuit for the cooling fan. I haven't been able to find diagnostics for that on the forum.

Could someone direct me to a link that describes testing for the cooling fan resistor, or other helpful diagnostics for the wiring and components to that assembly?

Much appreciated. [wrenchin]
 

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Remove the resistor and you should be able to test it with a DMM. If the resistor is the problem, then you should be able to make the fans come on by turning the AC on. If you have AC, but not charge, then unplug the AC clutch, and bypass the LP switch (which is located in the passenger fender) with a jumper. That will allow the fans to turn without damaging any other components in the AC system.

As far as testing relays, I believe that on the older Focis the relay is a standard 30a which is the same as the headlights. Swap the relay with another relay you can check to be sure it works. It's doubtful it's a relay, I'd expect fuses to blow before relays go bad. The location of the relay is in the owner's manual.
 

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Discussion Starter #3
Thank you whynot, I saw you to be an authoritative voice in the majority of overheating threads I read thru.

My resistor has continuity across the blades, 0 Ohms.

The rest of the suggestions I will test as soon as my order of parts shows up from the mainland and I reassemble the car. The fan assembly is sitting in my garage for now. I will post back with my other findings.

Thank you for the work-around on the AC, this 2000 has AC, but no workey.

More to follow.
 

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Thank you for the work-around on the AC, this 2000 has AC, but no workey.

More to follow.
For AC help, read this which is located at the top of the Technical Chat forum or in the Complete How-To Archive in my signature.
 

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Discussion Starter #5
Haven't forgotten about providing followup--I have a variety of parts pending delivery from several mainland sources, will hope they arrive by the weekend and I can get back into it again.
 

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Discussion Starter #6 (Edited)
Still awaiting parts, Water outlet housing PA6630GF, resistor F5RZ-8L603-AC, wiring harness YS4Z-8C290-GB all here. Awaiting Thermostat housing Motorcraft RH-122 on order, likely another week.

Having to wait a long time to get parts is just one of those punishments we have to endure in Hawaii. Call it the "paradise tax." Of course, I will be thinking of all of you souls who live where that white stuff falls while I'm working on my Jeeps or the rest of the stable in the 80* balmy tropical breezes of January.
 

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Discussion Starter #7 (Edited)
So the Focus is fixed, more or less. I have the thermostat housing on order now. The little snout on the top of it had broken off, I rigged it by tapping in a threaded barb as shown:



Problem was though that it had a small crack across the top, so when I had the entire system back together, ran it up to temp and verified the fan kicked on, it leaked from the crack that I hadn't noticed. That part is on order now and is the last thing to reassemble and I'll be back in business.

I figured I'd throw in a few things I figured out along the way, and add some info that I saw members asking in other threads about cooling/overheating woes.

Just about everything had failed in my cooling system--the resister was burnt out, the wiring harness was fried, the radiator was totally clogged, numerous hoses were aneurysmal/rotted or leaking, the water pipe (PN 98AB-8274BF) was cracked, and the water outlet was split at the seam across the bottom and leaking.

Water pipe photos X 2.



















It has been asked what the resistance should be across the resistor--I found that my burnt one had an open circuit and the new one showed variable resistance on repeated testing--the numbers kept settling on a different value, but the thing that is useful to know is that you will get some level of resistance across the blade terminals, and in the fried one you get an open circuit, sort of like what you'd get between your living room wall and your elbow......





So here are a few more photos so those learning can see where these items are.





New "Water Outlet" Mounts on driver's side of the cylinder head, just above the transmission, heater hoses run thru it and the thermostat and thermostat housing bolt to this part.





Part number/box label from water outlet.

 

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Discussion Starter #8
No, I am not trying to enhance my post count, but figured that was enough photos and text in one entry, and I didn't know if it would lock me out and I'd lose everything in the post.

So I found that after putting everthing back together, and running it to temperature I had the little leak at the thermo housing, and my low speed fan came on. I was a bit surprised that it did not come on until 110*C, and blew it back down to 104*C or thereabouts before it shut off. To me, that seems real hot before a fan kicks on. I tried turning on the AC, but "something" is wrong with that and AC clutch would not kick in. I tried jumpering across the low pressure switch terminals but that did not make the fan/fans kick on. Whynotthinkwhynot has already provided me with the AC troubleshooting link if I decide to work through that problem. Recall that this is not my car, I'm fixing it while babysitting it for the son of a buddy who went to the mainland for the summer. I also found minimal fluid in the PS pump reservoir, a few "rigged" vacuum lines that had collapsed so I replaced them. Basically this poor noble Focus is an emotional Black Hole of need. Yeah, he has totally neglected it while in college. [smackbum]

End of story, right? Not so EFFING fast..............

Next morning I came out to find a puddle of antifreeze under the "front" end of the engine, that is on the passenger side, so I drained it and tore into the thing again for the newly discovered leak in the water pump. It had previously not been able to hold any pressure enough for it to have manifested this for me to have known about at the start of the ordeal. Remember I said that basically everything was wrong in the cooling system. So now the water pump.................

Part number and details http://www.oreillyauto.com/site/c/d...=Search_01398_1362709_3176&pt=01398&ppt=C0331





Of course I used these threads from the forum to get thru that process, they were well enough detailed to make it not too difficult.

http://www.focusfanatics.com/forum/showthread.php?t=184383

http://www.focusfanatics.com/forum/showthread.php?t=153483

So again, it is just the issue now of getting and installing the new thermostat housing, and barring the subsequent discovery of previously undisclosed problems, I should be done.

I will also be replacing the blower fan resistor as this Focus only gets blown on "High."
 

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Discussion Starter #9
Okay, more followup as promised. The new Thermostat housing came in today so I stuffed it on, hooked up the hoses, filled the system and ran it around until everything came up to temperature, purged and was topped off. No leaks. The fan comes on fine. I will park it and let it cool down and look under it for any coolant puddles in the AM. For now I believe I'll call it fixed.

Thanks for your help and suggestions, hope my photos help someone. I'll add in a photo of the new thermostat housing and minor details once I download them.

[wrenchin]
 

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What caused the resistor to fry and burn up the lines?

Was he pouring rusty water in it? it looks like its been spraying rusty water all over inside the engine bay.
 

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Discussion Starter #11
Bower--resistors like this "just burn out." They don't last. This is the same type of resistor used in many vehicles in the A/C fan inside the passenger cabin. In that particular resistor it burns out and you end up losing the lower speeds of the fan sequentially until you are only left with high, then nothing. Some newer cars use a different type of resistor here, but they still burn out. Here's what one looks like in an 04 TJ Jeep Wrangler. While the older YJ Wranglers have the bulky metal coil type.



If you've wandered thru the forum, you've seen the A/C-heater resistor photos for the Focus.

They don't come cheap, most people don't know the reason their fans no longer work, and it is a real quick turnaround for the dealership to fix it very easily and reap a very large profit. It's known as planned obsolescence.

The rusty water was just that--water, without antifreeze spraying out of various broken plastic fittings on his Focus. I think it's a pretty good tribute to these little engines that it didn't overheat and just seize, or cause other damage as it was driven this way while continually adding water every trip until it came to "Uncle Opihi" to make it all better.

And this morning, I don't see evidence of any leaks in the cooling system. Woot!!

[wrenchin]
 

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Nah they dont just burn out, it sounds like they are the wrong value or a cheap tolerance. I think when mine fails im going to look into a mod to fix it. Wether i run the legs outside that little plug or get one with a larger surface.

It looks like its in a poor location also for cooling.

See when they design things they dont design them like they use to. When the fan motors are new they are more efficient and draw less power. Then they put parts in just over what they pull when new. What they dont consider is that over time as they wear a little they draw more power then the parts they have put in to just get by when its new fail.

If they put parts in that have a little more tolerance as the parts like motors get a little older the parts driving the fans would still be ok. The difference between a resistor made with a higher tolerance wouldnt be that much but it all adds up.
 

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saw this on another web site while trying to find a place that sells both the wire and resistor (still havent found such a place).

Aguy a few posts up from him said his dad cleaned the resistor and it made it work.

99% of the time it's the resistor connector. The prongs on the resistor get corroded causing a poor connection which causes the connector to melt inside. Sometimes if it isn't too bad you can clean the connectors and the fans will work fine. It's just not a good design, especially if you live anywhere where you get any amount of snow in the winter, there's nothing protecting the resistor or any of the connections from water and salt.
 

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Discussion Starter #15
So some more followup on this for those interested. I discovered that the high speed radiator fan wound not run. Having read thoroughly about Radiator fan issues here I have learned that BOTH rad fans should run when the AC is turned on and the engine is at ANY temperature. My AC blower motor would only blow on High, while the lower 3 speeds would not blow at all. Punching in the AC button would get me a green light on the button with no blow on speed 1,2, or 3, but when you then dial the fan to "4" or high speed, the fan would blow, but the green light would go out. I could not see that the compressor clutch was engaging either under any setting, and jumpering across the low pressure switch would not bypass this and make the compressor work. I have read threads here of other Foci with this issue but didn't find a resolution to any of those threads--generally whynotthink would respond with a remedy but no one ever closed their threads with the resolution to the problem.
I replaced the AC fan resistor RU1120 from O'Reilly's at $30.46 with about 20 mins of contortion under the dash and now the AC blower works on all 4 speeds as expected, but the surprising outcome I did not anticipate is that now the AC compressor kicks on as it is supposed to, and both the radiator fans blow at any engine temp like they are supposed to.
Once I download photos of the blower motor resistor with OEM part numbers etc, I will upload those to this string for completion. I may be done.
 

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Discussion Starter #16
As promised, here's the photos. This is the new AC/heater blower resistor and part number.



Side by side, old (white) and new (black)



OEM original part number.



Replacement part number.



I'm not sure why the PN was different orig-vs-new, but it works and this was what was consistently listed on multiple searches using the OEM PN.

At any rate, everything is working now and I've done a highway/street test drive of 20 miles and absolutely no problems.

Thanks all and Aloha [thankyou]
 

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The new part looks as if it has the 3 resistor values stamped into the back. I see 25K and 90K but i cant make out the first one? is it 0k?

And what does 50/10 mean?
 

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Discussion Starter #18
I certainly don't know. Perhaps someone with more knowledge and experience with these will chime in at some point.
 

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Can anyone tell me where is this located? On the fan assy?
You mean the resistor sensor unit?

Do a google search for "ford focus fan assembly" i believe it is between the 2 fans either at the top or the bottom.
 
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