AC dash question and Rear End noise Question

[Paintblend]

Here we go, 0n a 1996 f53 ford Newmar, the ac clutch will engage when the ignition swwitch is just turned on,, it has power to the clutch all the time even if the ac is turned off,,, what switch or relay would allow power to continue to the clutch even when it is turned off ,, something has to be stuck closed,, or in the contact mode,, you can unplug the clutch and it will unlock,, and my other question on this same unit 38 ft long with tag axle,, i hear a sort of winning noise from the rearend when it is in the neutral position,, i mean when you go down the road and you are not pulling and your not holding back it is in the neutral load zone,, what would cause the wine and is it something i should be concerned with> i hope i have described the questions well enough if not please ask me and i will try to answer better
thanks
steve

[W4MBG]

some cars use the a/c clutch (and load from the a/c compressor) to help shut down the engine when the ignition switch is turned from the run to the off (not lock) position. without any computer logic to tell it any different, the clutch would be pulled in whenever the switch was in the off position, or the a/c was on and the system was calling for cold.

some rear axles just do that. dont know about yours though. you could try draining/flushing the axle and refilling with synthetic gear oil. strain the drained oil through paper towels to see how much metal comes out.

[subford]

The A/C question does not have to do with the Ford part of the A/C system or the Motorhome brand of your RV.
It would depend on what brand A/C system you have in your Motorhome.
There should be a list somewhere in your Motorhome of all the Items the maker of the Motorhome put in it and what brand the units were.

If I were to guess I would say you have a bad control panel on the dash made by say Evens if it is an Evens unit.

You more than likely have one of two brands of A/C units.
One of the brands is Evens and I can not think of the other brand.
I will attach the wiring diagrams of the Evens systems in PDF form.
I hope this helps.

[subford]

By the way here is the Ford part of the wiring:




/

[Lt46]

The other popular AC installed in motorhomes was by SCS/Frigette, however I believe them to be out of business or bought out by another firm.
Evans website is: http://www.evanstempcon.com/index.php

[Paintblend]

thanks guys,, it is an evans unit,, i will use the diagram and try to trace out the problem,, if i unplug the control panel then there would not be power to the clutch,,right?,, but should the clutch run constantly and not cycle out,, what relay makes it cycle ,, it is almost like the thermostat relay is stuck on giving it power constantly,, but then the control panel should shut it off when you turn the ac off,, am i right or am i confused or am i confusing everybody else,, i will use the diagram and see what i can come up with,, and as for the rear end,, good idea changing the gear oil and lookinmg for metal,, i will do that as well,, thanks
steve

[subford]

Yes unplugging the control panel will stop (no power to) the Compressor Clutch.
There are no relays for the Compressor Clutch.
The Fan Relay does send power to the control panel when the key is in the run position.
I think there is a Thermostat in the Evens unit that cycles the clutch off and on.
But when you turn off the A/C at the control panel the clutch should never come in.

[Paintblend]

i unpluged the control panel head and turned the ignition switch on and the clutch engaged,, the control panel was completely unplugged and still the clutch engaged,, i then unplugged the high pressure switch and the clutch disengaged,, also if you unplug the low pressure switch it disengages,, there has to be something feeding it power maybe from the chassie side,, i cannot trace those wires because they are enclosed in a wire loom and wrapped really well,, what else could be sending power to the clutch
i am thinking about putting a toggle switch on the compressor and cycle it manually

[Paintblend]

how could there be power going to the clutch with the evans control panel being unplugged,, isn't that where it gets the power from,, somehow there is power going in reverse or from another source or from another point on the evans unit or chassie,, i am really confused now with the dash torn apart and 9000 wires hanging everywhere

[subford]

Do you have power on the Black wire with a yellow stripe at the control plug and does it go off and on with the key?
It does sound like some wire is shorted to the Black wire with a yellow stripe or the Purple wire it turns into.
The wiring diagrams all say these wires should be dead with the control unplugged.

[Paintblend]

yes there is power on that wire when i turn the key on and the power goes off when i turn the key off,, i haveunplugged the thermostat wires and it makes on differance,, but when i unplug the high or low side switch the clutch disengages (no power) where does the wire come from that is supposed to power up the clutch? it has to be a direct power source and that would answer why the compressor will freeze the coils because it runs constantly, even with the heat on

[Paintblend]

where does it change into purple maybe i can find that one and trace it back

[Airtool]

Think you may have a shorted Diode in the ground side,the diode is pictured in the drawing posted. The purple wire may run between the High pressure SW. plug and the compressor clutch connector,Black from the ground point and the compressor connection would be my thought.
do you have a DMM to test the circuit?

Dick

[Paintblend]

i have a volt meter,, i am not great with electrical,, are you talking about the diode on the ford chassie diagram,, and where would it be located? on which side of the firewall,, the blk and yel wire off of the compressor goes into a wiring tube so if i knew where to look for the diode i might be able to trace it back,,, something has to be feeding it power on the lower side of the low and high pressure switches,, because if you unplug one of them it kills the power to the clutch,, right? now after looking at the diagram, the power supply from the motorhome builder is before the switches anyway so that blows that theory sorry about being so dumb about this but i do want to figure it out and all help from both you guys are appreciated