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Discussion Starter · #1 · (Edited)
A couple of years ago my 01 ZTS (Zetec) had a short buried somewhere in the wiring harness, causing the motor to run roughly. I couldn't find it, so I took it to a shop (now out of business, prophetically and ironically). They claimed they found and fixed the short, and the car did indeed seem to run normally afterwards.

Except.

Following this repair, very infrequently, only on really hot days and only in slow traffic, the temp gauge climbed higher than it is supposed to. This seemed never to lead to anything bad, though - when I got moving again everything quickly returned to normal. I let it go because I don't fix things on this car unless they stop it from running or are a safety hazard. But on the last hot day of the year the temp gauge abruptly pegged, steam billowed from under the hood and I pulled over on a side street and shut it down. Most of the coolant was gone. I let it sit for four hours and came back with several gallons of distilled water, refilled the cooling system and started the car. Within seconds I could see that I had a major coolant leak at the thermostat housing. I slowly drove the two miles to home and put the car on jack stands, where it remains. I decided to replace all hoses, thermostat, thermostat housing and valve cover gasket. Before I finished all of the above however, (I'm really slow and have another car to drive) I found and read all the posts about the low-speed radiator fan resistor failing and causing the problem I seemed to have experienced. So I went out and got one of those, too. But when I went to install it, I discovered that the one I intended to replace simply WAS NOT THERE. Someone had removed it and directly crimp-connected together the two wires that are supposed to attach to the resistor. I installed the new resistor properly, double-checking wire polarity and all that, but right now I'm too chicken to start the motor for fear that I have or will cook something else electrical. In fact, I have removed the battery and have it resting quietly on a battery tender life support. It appears to be OK.

Any wise (as opposed to wise-ass!) speculation on what I should try next, or what might have been fried by driving the car for two years this way will be appreciated.

Steve B.
 

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Welcome to FF

I'll move this to the General Tech section for more looks & answers, that's the best place for repair help of this kind.

From what you've mentioned, there isn't an obvious reason NOT to just fire it up & see how it goes. Replacing the resistor pack for the cooling fan should help it work better, sounds like you were lucky for a while before the cooling leak caused a problem.

Hopefully the overheating didn't cause any additional ones.

P.s. - won't be able to find out if there are any other problems without a try, firing it up & checking it out is the next step.
 

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It would've been fine either way. When you bypass the resistor like that, then the fan runs on high speed when it's called for to run on low speed. That doesn't hurt anything. It will simply cool down quicker, and make more noise.
 

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Discussion Starter · #4 ·
Thanks - will give that a try. After the car cooled off and was refilled with water, it started right up and seemed pretty normal on the trip home - no oil leaks or funny engine noises.
 

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Discussion Starter · #5 ·
Thank you.Is it correct that if things are in order, both fans SHOULD come on immediately if the A/C is engaged? And if they don't, is it logical to conclude the fans or the relay that powers them is the next most likely point of failure?
 

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The fans are turned on with A/C when the PCM sees the refrigerant pressure rising in the system. There may be a slight delay after the A/C comes on before the fans are turned on. And, ambient temperature affects that too...the cooler it is, the longer the delay. On a hot (95+) day the fans come on about 2-5 seconds after the A/C clutch engages. The fans operate together...both on or both off at same time.

There are two fuses for the fans. A 30A for low speed, and a 50A for high speed. At least two relays are involved...mine has four relays.
 

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Putting the two wire together simply made the car have high speed fans all the time, the resistor being there gives you low fans. Only damage possible is to the fans which will be more worn being they ran faster all the time and they may well be unhurt.
 
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