Fan speed job done a differant way!

[BIGHVM]

Today I decided to have a crack at the fan speed fix as my blower only worked on 4 for a while now. So i took off all the connections as per some great pic threads here and this is what I found!

The pic of the connector shows heat damage to the plastic plug, so bad it has distorted.

The next view is a full on view of the same thing- showing that in the end of the thing are two prongs that have rusted so bad- they have come away from the resistor pack and fused to the female side......the word....Balls came to mind amongst others!

I thought about it and decided to cut the wires just behind the plug, strip them and tin them with solder. Then I set about preparing the resisor pack for solder by cleaning up the shoulders at the base of the resistors with a dremmel tool to remove all the rust I could and leave bare metal. I tinned this also and then soldered both to make a solid good join as seen in the last pic!

I then decided to box the resistor pack in a small project box I had kicking around for ages- its just big enough for the pack to fit it and is made from abs plastic with a rubber seal under the lid held on by screws-I had bought this from Maplins to encase a small amp I built, but used something else instead- I believe it was only a few pounds anyway if you are thinking of doing the same. The box fitted snug infront of the whole left where the resistor pack came from in the bulkhead.One point to note is if you have to fix it the way I did you will have to expose more of the wires by stripping back the loom a small way- around 5 inches should do!


Sorry they are a little blurred- its a rubbish camera in my phone!

I hope this helps some one stuck as to what to do in the same situation. If you have to do the job dont buy the replacement resisor pack unless you know your connectors are not beyond saving as mine where! It will be a waste of money and time.


The end result is- my fan now works on all speeds--Super!

 

[IZwack]

The pic of the connector shows heat damage to the plastic plug, so bad it has distorted.

I found the same thing on my Ford Econoline van - except on the rotary switch in the dash.
I dont know what it is about these things but they sure like to melt.

 

[BIGHVM]

Yes its just when a lot of resistance from poor contact, be it corrosion or loose contact generates heat....mine was toast like yours- really no way ot could be saved at all- so best option was take the fault out!
Feel satisfied today--the world is a better place now my Ex is fine again!

 

[Howard]

I hope your box is well ventilated as these resistors get mighty hot.

 

[BIGHVM]

I hope your box is well ventilated as these resistors get mighty hot.

Nope! Damn I better rethink that........approach then Howard- thats mate- by now it must have cooked the box! Oh well will look again later today.

 

[IZwack]

Fundamentally, the use of an old technology is what is wrong with this blower/fan setup - it is just a bank of resistors (each with different values) that transfers electrical energy into heat which is then radiated into the environment (firewall, air, etc..).

Ford should have chosen a more efficient/elegant design. For example, the Ford idle air control valve (IAC) is basically an electromagnetic solenoid which controls the amount of air leaking into the intake manifold during engine warmup. The depth of the 'plunger' in this solenoid is controlled through pulse width modulation (PWM). There is no reason why Ford should not use this same technology (PWM) to control the RPM of the blower fan. It is much more efficient (in terms of power consumption) and durable than a bank of resistors as there is no part which require exposure to the ambient air - which, when combind with the heat energy dissiparing from the resistor, increases oxidation on the surface of the resistor themselves. The PWM-based IAC is used not only in Explorers, but virtually all other Ford vehicles so PWM is a well known and tested method of control from Ford's perspective.