Cess, it should not affect the high speed, but chances are if you bought this used or from a junk yard, it may be possible this fan is shorted out or bad....

My guess is, if you cooling system is clean and operating normally, that MarkIV fan on high speed should be able to keep your D cool even under towing if the high speed setting is actually rated over 4000 cfm's. Otherwise, the speed your fan is currently running must not be anywhere near the 4000 CFM operating speed. The high speed may be partially bad or about to burn out totally.

 

Thanks Ken, That's what I am hoping for!

You say Mark IV? Did you mean Mark VIII or this a different fan all together?

I still have 3 weeks before Niagara. So I hope to try again with better results!!!!

 

I agree it's expensive. I just think switches make the D look like ****.(kinda redneck ish)

 

The nice thing about the controller is that you do not have to do additional external wiring. Less external wiring, less things to go wrong. Keeps everything as simple as possible and keep your D looking good without wires all over the place unless you spend extra time to dress up the wires.

 

Oops, Mark VIII, I was not sure what the model number was. It's the one we are all discussing about at the beginning of this message thread that Indy got everyone all wild up over!

As I stated earlier, if one of the speeds is burned out, it may be possible the other speeds are not in good shape either. I would definitely get another Mark VIII fan to do comparison and I would bet my last bottom dollar you may see a huge difference on an actual working mark fan and the one that is having problems. And remember, if you are doing the wiring yourself and using those relays to do the work for you, make sure that "at any given time" there is no power going to all the speed power leads, this can shorten or completely ruin your fan motor. You can only power one speed lead at any given time. Working with relays, you have to make sure when one switch is turn on for one speed, the relays must also disconnect power to all other power speed leads to prevent the motor from working against itself.

 

Ken,
I used the schematic found in post 105 of this thread. Check it out and see if looks good to you. I got it from rtkota5point9. He says it works for him. I'm just a monkey following directions as far as the wiring goes. I am clueless when it comes to electrical stuff. Though I may ask the electronics guy at work to help....

 

Looking at the schematics to the other link, here is your possible annoying problems you will have to deal with.

1. The fan will always stay powered on at low speed as long as the key is on the run position. This is not good if you run your D during the winter time, it will take longer for your D to warm up.

2. You will have to manually flip the switch between low and high speeds based on load demand you put on the engine. This is not really a safe thing to do if you are driving on the highway and you are taking your eyes and one of your hands off the road and steering wheel to flip a switch.

3. Also, this diagram does not interface your A/C to work alongside it. So when A/C comes on, you have to flip the switch to high speed unless constant on low speed will suffice for A/C cooling (which may not as the D will get hotter with A/C running).

This is what I recommend if you still want to stick with this home made relay setup:

2. Replace the switch with a thermostat. Let the thermostat automatically switch to high speed when the temperature reaches the set point (180 or 195 depending on your T-Stat you have.

1,3. You can add a third relay to the schematic. To switch on/off the low speed via A/C. If the low speed of the MarkVIII is at least over 2000 cfm's, it may be enough to cool the A/C condenser. If this is not enough cooling for the radiator, the thermostat on step 2 will take over automatically by switching the fan from low to high speed.

All in all, the fan will only power on when demand isrequired of it instead ofthe low speed running all the time regardless of load.The thermostat will automatically switch the fan from no speed/low speed to high speed instead of having to manually switch it.

To tell you the truth, most bigger cars, usually just have one speed. The two speed may be used in the lincolns to deal with noise levels. Running low speeds when the engine is not running at high temperatures and most time, is enough to keep the engine cool when you are only idling.

I reworked that schematic I saw by adding a 3rd relay to actually control the on/off of the low speed via A/C power. By then, there is alot of little wiring, here and there, and can confusing the amateur person that knows little about wiring. Best is to get a dedicated fan controller. Yes, the one that is expensive option to this homemade brew. But the fan controller eliminates all the extra wiring and possible errors. But when choosing a fan controller, make sure you choose the correct one. Most fan controllers only controls one speed or 2 fans. You will have to research to see if they make a fan controller for a 2 speed fan, not for two separate fans. big difference. The one that Meen green got may have been setup for two separate fans.

 

I'm an amateur Ken, But I can follow directions!!! If you would be so kind to tell me how to add a 3rd relay I would be very thankful! Ultimately, I'd Like to have a switch for Low also. I see your point on the switch, but is really any different than eating, cell phones or radio controls? I'd also like a true temp gauge inside the cab.

 

Alright, if you are willing to tackle a home made setup, I will modify the current wiring diagram with a 3rd relay so the low side can be controlled as well. Give me some time as I will have to use something like Visio to draw up the diagram and convert it to something like PDF so you can dload it and open and view it.

 

Ken, don't go to to much trouble. If you want to tell me which number to put to which, I can draw it out. thanks though!!