[RegaNewell]

Thank you Richard for all the information.  I contacted Newell and had a great conversation with a Gentleman named Robert.  He stated that the yellow wire does indeed come from directly from the DDEC.  Newell adds nothing to this circuit, to monitor or change state of the relay.  I will have to get with a Detroit Diesel Shop (The DDEC was changed out at "Big Cabin Diesel" in 2014)  They have actually changed all the filters and fluids on our Coach for the last 12 years.  They also performed the 300,000 mile value clearance and adjustment. While I had Robert on the phone, I asked another question.  I told him how I had a 6th Breaker in the very rear electrical Panel with no label, but it had a Purple Wire connected to it.  I told him that I had a friend that also had this breaker (with purple wire) and it was Labeled "Link 2000".  What in the world Is link 2000, and what is its purpose.  Robert explained it to me, that this purple wire goes to the inverter controller, sometimes in the Kitchen Galley above the stove. This monitors the difference in Voltage between the house batteries and engine batteries, and will generate a code on the controller display if the starter batteries are low, as a Warning or Error Code.  This is information that will allow you to choose to Merge your batteries and allow the starter batteries to be charged also.  I told him how Coach 427 did not have this breaker, but mine did (Coach #432), and that Coach 512 also had this breaker.  He stated that since our Coach was a show coach (Tampa Show) that ours may be the first coach with this option.  He stated they always tried new things with a show coach.
I cannot believe that I started in on Post #11 of this thread and did not read the previous post (1-10). I actually spent over an hour searching this forum that had anything to do with (Fan Control, Fan Relay, Hydraulic Fan etc..).  I was a little overwhelmed with how many pages came up on these searches, 63 pages, 27 pages, 42 pages.  I need to either use better words in my searches or spend more time looking through all the threads..  The information is there, I just did not spend enough time searching, my bad.
Pam is actually setting up an appointment with Big Cabin to have the fluids, filters, and greasing completed.  I will talk with them about this issue and go from there. Of course this all depends on when I get the Coach where it can drive down the road again.

Thanks again for everyone staying with me during these long post's.

[Richard]

The use of AND in the search term is invaluable. If you type in. Fan AND hydraulic, you get results first that contain both words. If you type in fan hydraulic you get all the threads with either fan, hydraulic, or both in the thread.

AND in all caps

[Richard]

I am not sure about this fan control relay operation.  I know that Terminal #4 has to be grounded to make this relay work. I did my best to trace out this yellow wire that needs to be grounded.  I was able to follow it under the couch until it went up through the floor.  I could not find it any where under the dash or the front terminal panels.  Now I am wondering if this system actually breaks the ground to change the energized state of the relay.  I assumed that since the power came from the DDEC that it would know when to shut off the voltage when it needed the fan to run in high speed.  The 12 volts may actually stay hot all the time and the ground is the control.  Well I wanted to know if everything would work since I removed the front switch, unhooked the spares, and wired the relay as I think it was from the factory.  So I put a jumper on the yellow wire (terminal #3 on the relay), and started the coach.  The fan was running put I was not sure if it was running in high or low speed.  So I pulled the solenoid connector apart and the fan instantly went into high.  I put the connector back together and the fan went to low speed.  I had a smile on my face and was happy, this only lasted about 30 seconds.  The fan started changing from low to high and was fluctuating.  I moved the connector around and the speed would change, then it went into high and stayed in that state.  Then I found out why. One of the wires going into the coil had broken off right where it goes into the coil. Sometimes I just want to cry.  I am now going to remove the solenoid coil and see if I can repair it, or have to order one.  I believe I will call Newell tomorrow and try to talk with someone that can explain the correct operation of this circuit.  I included a couple pictures of the coil.

So, I am confuseded. You said earlier you don’t have a ground on Terminal 3, the yellow wire. In this thread, you stated the fan works great except for the broken electrical connection on the solenoid coil. Did you ground terminal 3? If you didn’t, how is the circuit triggering the fan control relay? I am just trying to figure out if you have a problem other than the intermittent connection on the coil.

[RegaNewell]

Richard, thank you for the information on searching, I will definitely use that option in the future. After reading your post and my past post, I too was confused with my verbiage!

Terminal #1 on the bottom of the relay is connected to terminal #4 in the panel. (orange wire)
Terminal #1 and terminal #5 on the bottom of the relay are jumpered together.
There is no terminal #2 used on this relay.
Terminal #3 on the bottom of the relay is connected to the fan speed solenoid. (Orange/Black Stripe wire connects here)
Terminal #4 on the bottom of the relay is the ground for the relay coil which is controlled by the DDEC. (Yellow wire connects here)

I applied a ground to terminal #4 with the yellow wire removed from the relay. I just wanted to see if the fan would run in low speed, which it did. I fixed the coil, ( it works) but will still order new coil and solenoid valve, and will carry as spares. Robert at Newell stated that this signal on the yellow wire (terminal #4 on relay) is controlled from the DDEC. I am actually going to hook the tracer back up and try and find it at the DDEC, (just because).

I need to pay better attention of what I am actually typing, my brain new what I meant, my fingers didn't get it right.

[Richard]

Just confirming. With key on, you do not get ground on terminal 4, the yellow wire?

[RegaNewell]

Richard,

Correct, With key on, I do not get ground to the yellow wire that goes on terminal #4 of the relay.  I have 48Kohm's between yellow wire to ground, with key on or key off.  I did trace the yellow wire to the DDEC. @Richard and Rhonda Entrekin

[Richard]

That is in the ballpark of what mine measures.

[RegaNewell]

Richard,

Does the resistance drop on the yellow wire when you turn the key on. I tried it with the key on, key off, and engine running, no change in resistance in all three states.

[Richard]

I hate to keep asking dumb questions, but can I assume that the relay does not cause the fan to run on low when the engine is running?

Since you found the yellow wire on the DDEC connector, can you backprobe the connector to see if the problem is the DDEC or a problem with the yellow wire.

It will be tomorrow or Sunday before I can run the test with OFF ON RUNNING.

[RegaNewell]

Richard,

You are definitely not asking "Dumb" questions, it is the corrupted data that you have to work through. ! The questions you are asking makes me realize I should do more thorough checking, better troubleshooting, and have good verified information before I post my findings. Please continue to help me in my troubleshooting skills, it is appreciated.

Jeff