Need help identifying an intermittent sound

[Mr Phatnold]

I need a bit of help. We have a sound that comes on briefly and it sounds like a pump. The dealer wants the truck for three days and they don't have a loaner program.
It runs year-round and I switch off the ASS system every time I drive. The sound does stop when I turn off the fan.
Any thoughts would be great. Check out the video.

Sponsored

 

[airline tech]

I would drop the blower motor down and inspect for it being full of leaves.
It sounds like it is struggling to spin freely, extra weight - imbalance.

 

[airline tech]

Plus,also check for a spring clip - laying in the blower squirrel cage or near the opening of the housing.
This is a balance weight for the wheel.

 

[Mr Phatnold]

Thank you for your advice. I dropped the fan and it was clean. Maybe the fan is just bad???

 

[Mr Phatnold]

Here

is a picture

 

[airline tech]

Now it sounds like a fan issue but there are some other things that the noise could be and it is stopping when you turn the system off.

1. Coolant Heater - Pump, this should only run when in (Auto-Stop) and in heat mode, this pump takes place of the water pump (when engine is off) to help keep the cabin warm.
It's located beside the Coolant Reservoir (Tank)
It may be stuck (on) and running along with the water pump adding more pressure through the heater core (noisy)
I do not have (ASS) but do have the pump - and I can activate it with a scan tool, but it will never run on its own as its not needed. I triggered it on with my scanner for curiosity.

another thing - as I suspect you were there (is good) - is the cabin filter clean?

But from the video sample - it does sound more like a blower motor issue.

It's hard to tell from the pic, but there should be a balance weight on the cage like this or similar.

On-Line Pic

 

[airline tech]

Cabin Coolant Heater Pump

Possibly feel this for vibration with the engine running or with a scan tool you can see it (on or off)
With engine running this should be off. Its electric and only runs when ASS is active, and you are calling for heat in the cabin.

 

[Ranger_Rocks]

...
It's hard to tell from the pic, but there should be a balance weight on the cage like this or similar.

On-Line Pic

 

[Mr Phatnold]

Just a quick follow up on this issue. One small note, this is my wife's truck so I don't drive it much.

When the "pump noise" goes on it goes away once you give it gas. The only thing I can thing of is, the issue is the ASS coolant recircling cycling pump not operating correctly.

I think she is done with the truck because of this.

 

[airline tech]

Ok,
The only thing that makes sense is the Blower Motor (itself) or a power & ground issue.

1. You can make the noise (STOP) by turning off the Climate Control
2. The noise (Stops) or (Dissipates) when you give it gas

The (Cabin Coolant Heater Pump) should only be triggering (ON) when the ASS is active, engine stopped - Key on and waiting engine restart

When the engine is running the water pump is (Always) pumping coolant through the heater core, no matter if the Climate Control is On or Off, so turning off the Climate Control at engine idle is not stopping the flow of coolant through the heater core, so the noise would still be present, if this was a coolant flow issue.
Although the noise you have does sound similar to coolant flowing through the core (Air Pockets)
it would still be heard - no matter if the Climate Control is On or off.

AC - The AC freon flow is only flowing through the Evap Core when the AC Compressor (Clutch) is (ON), this noise is more of a Hiss - if this would be an issue

So that leaves the Blower Motor & Incorporated (Blower Motor Control Module)

There are 3 wires feeding it:
Power - From the Blower Motor Relay
Ground
FCIM - PWM (Pulse Width Modulated) control

The FCIM sends a Power Signal to the Blower Motor Relay (Coil Side) when you command the climate control (On)
This action (Closes) the Blower Motor Relay which feeds power to the Blower Motor

So that is how its powered

To control the Blower Speed - the FCIM pulses Power wire to control its speed

To CONFIRM its the Blower Motor, when it is making the noise, get a mechanics stethoscope or a screwdriver with a plastic handle and listen to the blower motor or feel it for vibration.
and then give it some gas and see if the noise stops.
Plus - when it is making the noise - try to (Ramp) Up the blower speed with the Buttons, will it go to Full (Hi) and does the noise stop or get more pronounced or does it appear to drag and no change in speed.

What I think is happening is the Blower Motor (internally) dragging down at (Idle) RPM Voltage, and when you give it gas - The Voltage is bumping up slightly and the blower motor is overcoming that drag.
Basically at (Idle) its underpowered.

One could do some wiring checks to confirm its not power or ground related.

I would also try - Pull & Reseat the - Blower Motor Relay in the (BJB) Engine Bay Fuse Box and inspect the contacts.
You can also check (Pull & Reseat) and check the contacts of Fuse #79 in the BJB, this fuse is mounted on the bottom side of the (BJB) and requires removal of the BJB to get to the bottom side of it.

Power & Ground (Check)
Disconnect the Blower Motor Connector

With Key (On) and Climate Control (On) check Pin #2 on the connector to ground, should be reading full battery voltage, if low voltage reading start engine and give it gas, does the voltage climb to what the (Engine Running) battery voltage is.

Pin #2 - Yellow/ Green Wire

Then check Ground - Pin #3 (Ohms Scale)
Key Off - Pin #4 to a Good Ground source - should be 3.0 Ohms or less
Pin #4 = Black / White wire

If you have (High Resistance) then we need to find the Ground Point G225, as that is where the ground feeds to.

I am not concerned with the PWM Control Pin #3 unless you are unable to control fan speed

The actual location of G225 is (?) as this is the only diagram that shows it.
It states engine bay, but this diagram shows it near C211, which is in the row of 3 connectors behind the RH (Passenger) Footwell Kick Panel, so I am assuming it is somewhere near the blower motor. (High Amperage) draw motors generally do not have a long ground run.
The Only wire running to G225 is from the Blower Motor, no other grounds are routed to it.

My hunch is the blower motor is internally worn, or you have a voltage issue (low) voltage at the Blower Motor (when at idle)

Sponsored