Symptoms of a Bad or Failing Cooling Fan Resistor
by Lorne Goldman, Rick Frazee & Jonathon Hoyes

Common signs include the engine overheating, cooling fan only working at certain speeds, and the fan never turning off.  Virtually all modern vehicles built today use electric cooling fans to help pull air through the radiator to keep the engine cool. Once the coolant temperature sensor detects that the engine temperature has exceeded acceptable levels, the cooling fans will be activated to keep the engine cool. Many vehicles come equipped with cooling fans that operate on more than one speed setting. This is made possible by routing their power through the cooling fan resistor. The cooling fan resistor is an electrical resistor that limits power to the fan in steps, so that the fan can operate at different speeds according to the cooling system’s demands. Since power to the cooling fan is sometimes routed through the cooling fan resistor, when it fails or has any problems, it can cause issues with the regular operation of the fans, which can lead to overheating. Usually a bad cooling fan resistor will produce a few symptoms that can alert the driver of a potential problem that should be serviced.

1. Engine overheats: One of the first symptoms of a potential problem with the cooling fan resistor is engine overheating. If the cooling fan resistor fails or has any issues, it can cause power to be cut off from the cooling fans, which can lead to overheating. Any sort of overheating issue should be tended to AS SOON AS POSSIBLE
to avoid the possible engine damage.


2.
Cooling fan speed issues:  Another symptom of a possible problem with the cooling fan resistor is issues with the cooling fan speed. If the resistor breaks or has any issues it may cause the fans to only function on certain settings. The cooling fan resistor is meant to send power to the fans in steps, so that the fans may operate at different speeds. If any of the individual steps or switches fail, it will disable the cooling fans from operating on that speed setting. You may notice that the cooling fans only operate at one speed, when they used to operate on two or more.

3. Cooling fans never turn off: Another symptom of a potential problem with the cooling fan resistor is cooling fans that stay on at all times. If the resistor shorts or fails, it can cause the cooling fans to stay on even when they are not supposed to. In certain cases, the cooling fans may even stay on when the vehicle is turned off, and will create large draw that will eventually drain the battery. All of these things can be rectified. Contact me.


4. Ford Rad Fan Dual Speed Resistors As the MMC no longer makes these cars or any other traditional Morgan and its dealer are contractually bound to buy from the MMC, I feel odd suggesting that moggers buy standard Ford parts for a price so much higher than they can be had from your neighborhood Ford factor. The surest solution is the one adopted by the millions of the Ford vehicles owners using this system. Merely switch to a single speed fan by removing the resistor. See the GoMoG Law below.



GoMoG Law of Simplicity: The More Complexity One Incorporates Into a Sports Car, the More Its Performance and Reliability are Prejudiced. Sports Automobiling is a sport. (duh!) Unlike road cars, they should be designed as one would a golf club or a tennis racket, namely, to be reactive and express the skill of the driver in the clearest way. Ages ago. Morgan stumbled into this home truth during the Golden Age of Automobiling in the 1930s and was able to keep a hold on a small and fiercely loyal crowd of fans, which included a disproportionately large percentage of famous racers and hand's on amateur mechanics for generations. By chance, the MMC developed a simple sports vehicle that was packaged in a lovely shape, using very commonly found engines and that COULD be tweaked to have a supremely comfortable suspension by savvy owners. Unlike other sports car fare, this simplicity, reliability and comfort owners allows them to go long distances with confidence, despite the super thin support infrastructure. Morgan production justifiability achieved the name of The Last of the Real Sports Cars.

The company, under its third generation management, abandonned this formula and began to cater to a different market that pleased him more..despite the wholesale loss of its old market, its assets, its reputation for no-nonsense machinery and product support. Government grants kept it afloat, (Politicians are not auto mechanics) In the end, the divided family was forced to sell the Company for less than the grants it had received in the years leading up to that sale, a small fraction of what it was worth 25 years before. Now it produces vehicles without any real connection to the line that lasted 110 years. The current design does NOT encourage interactions between owners and their Morgans. The engines are much rarer and infamously expensive to part-support and the addition of unfocussed accessories makes the cars less reliable, if warranty claims and the GoMoG Inbox can be used as a judge. :( The new cars are what they are designed to be, plush retro-looking touring cars. This article addresses one issue that cropped up with the new MMC mentality. There are scores more. I deal with this one because
I very much respect the early Roadsters and I host their Group on this facility.

The world and our communities would be better served if new MMC would stop trying to convince everyone that the current cars are the same now as they were for a century. A superficial shell does not a sports car make. It does neither community, new or old, a beneficial service to try and convince any that it is otherwise.