Mark VIII 3 wire pin out

[roverz]

Looking for helping identifying the three wire pin out on the Mark VIII electric fan. Looking at the connector on the fan motor from Left to Right.

There are two Black leads and one light blue lead. When i connect a Battery charger 2amp, 10amp I connected the Negative to the light Blue Lead and the positive to each of the black leads. When the battery charger was set to 10amp one of the black leads gave me a slow fan rotation and the other lead just gave me a humming noise with no actual fan start up.

Unfortunately also i think the fan might have turned in the opposite direction that i had desired.

 

[Maniak]

Some of them are single speed units. The one in my 78 van and the one in my friends f-150 are both single speeds...

IIRC bottom wire and the middle wire are tied together internally. The top wire is ground.

Also, that battery tender doesn't have enough power to run the fan. Startup is 60amps and run in 30 amps (thats single speed mark VIII fan).

~Mark

 

[roverz]

Mark, On my fan thou when testing it on a test bench i kept the battery charger negative lead on the light blue lead from the fan motor and rotated the positive lead to each of the black leads from the fan.

One of the black leads caused a semi-slow fan rotation thus leading me to believe the fan was good and could be used.

But the second connector didnt seem to turn the fan at all just a low humming noise.

IF the both of these leads were tied together than you would think the experience would be identical since they are basically two ends to the same wire?

 

[Maniak]

Assuming it is spinning the right way that could be right. If you can't get enough power to start the fan it could just hum (I've never tried that)..

So, possibly the wire that causes it to hum is high speed, the one that makes it spin is low speed and the blue is ground.

Also, it just occurred to me, I don't think I'm using the factory plug. I think my plug is a replacement plug from the parts store so my colors may not be right.

~Mark

 

[roverz]

Mark,

The other thing that is throwing me off is that i have connected the Flex Lite VSC controller to both black leads for the (+) connection and on one of them it works although it seems to be low speed. When i connect it to the other lead it blows the 30amp fuse supplied with the VSC. My understanding is that the VSC controller was able to handle the Mark vIII power draw but now i am guessing that the working lead is low speed and the other lead is high speed and the high speed lead is trying to pull more amperage than the VSC and 30amp circuit can handle.

What options do i have?

Only use the VSC for low speed fan operations. Use the VSC to control a higher amp Relay to connect to the High speed lead. Which i guess would mean that i would only ever have high speed single speed operation.

 

[Maniak]

I don't remember if the Flexalite VSC can handle the Taurus/Mark VIII Fan pull. I thought I remembered reading that one of theirs could and another could not.

Assuming it can, you would use the VSC on the high speed connection only..

First thing we need to figure out is what wire does what. I think you can see the connections in the fan by looking through the vent at the back so you can see if any are tied together. I can't remember if you can pull the back off on that motor. Worst case, use a battery and big wires (10 gauge or so) and figure out which wires make the fan run at which speed and with the correct direction. That is what I did when I first got my fan in the yard (while testing it).

If you connect the battery to the fan and the motor spins in the correct direction then you know that you have the negative in the right spot. If it goes backwards the ground for the fan is where you have the + connected right now. If it arcs bad and doesn't spin then your most likely on the 2 positive connections.

Once you know for sure you have 1 or 2 speeds and which wire is which then you can add the VSC to the equation.

~Mark

 

[roverz]

Ok so spent the weekend working on this problem again and determined the low and high speed connections along with the ground. Now the fan is spining the correct way and have added the VSC back into the mix, unfortunately I am blowing 30amp fuses with some frequency. I had hoped that the low speed wire wouldn't pull more then 30 amps on start up but now i am suspicious about that?

I called Flex-a-Lite this morning and they said that the VSC is rated and tested for 45 AMP continuous so i should be safe to change the 30amp inline fuse for a 40amp, but I am still suspicious if this is going to solve my problem.

And all of this still leaves me with a low speed only fan connection?

1. One though is to use the VSC to connect to a 75amp Relay Tyco that i just ordered but i most likley would lose the gradual cycle on feature of the VSC controller?


Any other options that anybody recommends besides the obvious of changing the fan or the VSC controller to one that can handle the power surge at start up?

 

[roverz]

Just adding to my list of question-

Lets assume that the switch to a 40 amp fuse does allow the VSC to controll the Mark viii fan on the low speed connection.

Is there any way that i could still use the VSC and another option on the High Speed connection for Hot days or when i am towing?

Was thinking maybe a manual switch to a 75 amp Relay or something but what would happen if the VSC was supplying power to the low speed wire and I manually toggled on the High Speed wire of the fan?

 

[Maniak]

The Mark VIII fan pulls just over 30 amps when running so depending on how "soft" of a start you get, the 40 amp fuse and controller should be able to run it on the high speed. If it can, just use the high speed side.

If the controller can't control the high speed side you could run a seperate 75 A relay on the high side but I don't know what you would use to trigger the relay.

If the VSC you have now has a "on full" type output at a certain temp (maybe for a 2nd fan) you could use that to trigger the 75A relay. If it doesn't you could use a 2nd controller (like the adjustable hayden I'm using now) and set it to turn on at a temp higher than the VSC is already on full.

One thing I did learn though is you don't run the low speed and high speed at the same time. That means you may have to end up with some other relays to make sure when one is on the other can't be on.

~Mark