Dash Fan

[barluis]

We have a 1997 32CG Holiday Rambler Vacationer. It is built on a Ford 1996 Chassis with a 7.5L 460 Engine. We have had this motorhome since July 1996 and from the beginning the dash heating/AC did not work. After many days in the shop the Dealer patched the system and got it sort-of-working. We got tired of driving from Amarillo to Lubbock to work on this problem. After some time I was able to get the fan working with the heater. The AC never really worked.

About three years ago I found a problem with a signal 12VDC wire, corrected it and at least we could count on having the dash heater working. This Spring the fan refused to work again. The cause is the same: No 12VDC to feed the motor! Out of the two wires that feed the motor, the 12V signal comes from a white/brown wire and the other one goes to ground.

This white/brown wire is connected to a red wire and there is no 12V here! -- The fuse is good, I replaced the relay just in case, checked continuity for these wires and so far I haven't found any area open. This 12V come from a ghost connector! I haven't found it and would like to know if anyone out there have followed these wires and could help me locate the open source.

I am still mystified since when I parked it, the fan worked perfectly! So I am still working on the theory of rodent-cause opening. Nothing so far. I am thinking on rewiring this fan directly by adding the 12V to the common connector at the fan switch/resistor connector so can change the speed. The fuse is a 20Amp fuse, so I need to make sure to use this same area and feed the output wire from the fuse box to the control SW. Have any one done anything close to this? I REALLY would appreciate any idea on this subject

[wolfe10]

Any Ford dealer should be able to get you a wiring schematic for your dash HVAC fan.

Armed with that, troubleshooting will be a lot easier.

Brett Wolfe

[barluis]

Any Ford dealer should be able to get you a wiring schematic for your dash HVAC fan.

Armed with that, troubleshooting will be a lot easier.

Brett Wolfe

I have a schematic I got it from Monaco. That's how I was able to trace the wires. However, Ford's dash wiring and Holiday Rambler's do not match since the controlers are after market and not Ford's system

[wolfe10]

I have a schematic I got it from Monaco. That's how I was able to trace the wires. However, Ford's dash wiring and Holiday Rambler's do not match since the controlers are after market and not Ford's system

What aftermarket dash HVAC (including fan) do you have?

[barluis]

What aftermarket dash HVAC (including fan) do you have?

I am not sure what brand this thing is. Today I ruled the fan motor as dead. The brand of the system is "SCS/Frigette (Specific Climate Systems, Inc.) The biggest problem with this situation is not the lack of knowing WHAT to check it is rather WHERE to check it. In the early days while it was still under warranty whoever worked on it rewired the 12volt source. I can't find! I am hoping that once the fan is replaced It will work.

If you follow the schematic/wire diagram, there is a RED/BLK wire that it is supposed to go all the way to the fuse block. It doesn't. it winds around and goes into a three wire connector and the line converts into a solid RED wire. However, there is no continuity from here to the fuse, nor it has 12V to be used by the HVAC circuit.

The Fan SW, Resistor and thermostat are working perfectly. By feeding 12V into the circuit directly from the Fuse I can check the position control module, the Fan SW and the Resistor by looking at the voltage drop on the voltmeter. I can also make the servo motor work.

If I can not make the Fan Motor work after replacing it, I will install a line that will closely follow the schematic I have.

My next step is finding WHAT type and Brand this fan is. I was not able to see any labels from where I was looking. It seems it is going to be a very close and uncomfortable procedure, since I can't remove the Co-pilot char that easy. It is bolted underneath out of reach for simple tools. Replacing it with the chair still in place is also a very hard place to move around.

[wolfe10]

Today I ruled the fan motor as dead.

However, there is no continuity from here to the fuse, nor it has 12V to be used by the HVAC circuit.

To contact them: http://scsfrigette.com/hvac-systems-recrea...al-vehicles.php

I am confused by your statements. If no 12 VDC to the motor, how do you conclude the fan motor is dead?

Have you jumped 12 VDC positive directly to the motor-- that would run the fan on high, as the resistor is what gives lower fan speeds?

Brett Wolfe

[barluis]

To contact them: http://scsfrigette.com/hvac-systems-recrea...al-vehicles.php

I am confused by your statements. If no 12 VDC to the motor, how do you conclude the fan motor is dead?

Have you jumped 12 VDC positive directly to the motor-- that would run the fan on high, as the resistor is what gives lower fan speeds?

Brett Wolfe

The 12V that feeds the fan was not present. This is Red/black wire that comes all the way from the fuse box and it was open somewhere. I could not find the place. The fan itself was also dead. The motor shaft wouldn't turn. I was able to check all the wiring with a schematic from SCS Frigette. This company sold me a new motor and after installing it remained silent. It wasn't until I fed a new wire from the fuse box with a wire I installed and connected to the original location on Connector C100 (D) when I got the entire system to work the way it is supposed to. (I cut the original wire off). Now the fan changes speeds and the heat will come out of the dash when I move the thermostat control.

[wolfe10]

The 12V that feeds the fan was not present. This is Red/black wire that comes all the way from the fuse box and it was open somewhere. I could not find the place. The fan itself was also dead. The motor shaft wouldn't turn. I was able to check all the wiring with a schematic from SCS Frigette. This company sold me a new motor and after installing it remained silent. It wasn't until I fed a new wire from the fuse box with a wire I installed and connected to the original location on Connector C100 (D) when I got the entire system to work the way it is supposed to. (I cut the original wire off). Now the fan changes speeds and the heat will come out of the dash when I move the thermostat control.

Congratulations on solving your problem. Two problems occurring at the same time (open wire and bad motor) is unusual, but as you did, just approach it logically.

And glad you replaced the open hot wire from the fuse box-- those always scare me. Sometimes one or two strands of an open bare wire (which can happen if a wire is broken) can contact ground and while still not drawing enough current to blow the fuse turn those few strands red hot and start a fire.

Brett Wolfe