FM radio static

[FordMan4X4]

Now that the weather has changed in Michigan when I remote start my 2019 Ranger and get in and hit the start button the heater is on and the rear defrost is also on. The radio is set to FM and it has a decent amount of static. I tried a few things and when I turned off the rear defroster the static is gone. When I turn the rear defroster back on the static returns. Any ideas what is causing this to occur?

Sponsored

 

[RangerBill]

Now that the weather has changed in Michigan when I remote start my 2019 Ranger and get in and hit the start button the heater is on and the rear defrost is also on. The radio is set to FM and it has a decent amount of static. I tried a few things and when I turned off the rear defroster the static is gone. When I turn the rear defroster back on the static returns. Any ideas what is causing this to occur?

Is it static or a whining sound? If a whining sound, it might be the alternator making the noise in the radio under a high current load from the defroster grid. Does the pitch change with different engine RPMs? If a static sound, it might be a loose connection to the grid or a cracked window heater grid that is barely making a connection, producing the static in the radio.

 

[airline tech]

Bad connection on either the Rear Window Heat or Heated Mirror - Circuit.
Creating a circuit disruption and electrical interference is the most likely.
First - check the connectors on the window, pull and reseat - be careful as these are delicate and I suspect a bad (solder) at this point.

 

[airline tech]

I did not take a full dive into this.
I am looking for close proximity pins in the connectors or harness runs
A suspect connector to check for bad / dirty connection.
My HUNCH is it's on the heated mirror side of the circuit, using the logic that the heated mirrors run with the speaker wires.

You may also note: Is it reception static (antenna) or speaker and if speaker (ALL or Specific)
To help in pinpointing down which harness run its in.

A suspect connector to check for bad / dirty connection
Pin #8 = Left Heated Mirror - Heat Power
Pins 1 &2 = LF Door Speaker

Check Pin #8 - ensure its clean and secure in the cavity

 

[FordMan4X4]

It seems to be reception static from all speakers and engine rpm does not effect it. I unplugged rear window defroster connectors and plugged back in without any problem. Looked over the defroster lines on the rear window and saw no possible breaks in them. Pulled the left kick pad trim to review C213 and do not know how to disconnect the connector. Did do a wiggle test on the wires of that connector.

 

[RangerBill]

It seems to be reception static from all speakers and engine rpm does not effect it. I unplugged rear window defroster connectors and plugged back in without any problem. Looked over the defroster lines on the rear window and saw no possible breaks in them. Pulled the left kick pad trim to review C213 and do not know how to disconnect the connector. Did do a wiggle test on the wires of that connector.

Did you run the engine with the rear window defroster unplugged for a test?

 

[airline tech]

Since it appears to be in the (Heating) circuit
Let's try to isolate -The Mirrors & Rear Window and Switch (Ground) to the Relay Coil

At the BJB - Engine Bay Fuse Box
Pull Fuse #37 - This is for the Mirrors (Problem Remain?)
Pull Fuse #68 - This is for the Rear Window (Note it is on the bottom side of the BJB, must remove the BJB to access the bottom side fuses. (Pull the fuse and temp install the BJB)
(Problem Remain?)

If problem remains - Both Fuses Pulled and you press the Rear Window Defog - Switch and it still produces an issue - then the issue is in the (Relay) Coil Power & Ground and most likely in the Ground Circuit for the switch to the coil

The Defog Relay is integral to the BJB:
The switch on the FCIM provides the ground for the (Relay Coil) via manual input by driver or automatic via MS-CAN (Remote Start) pulse the switch to Ground.

So, we need to try to isolate it down as which power feed is causing the issue or is it a grounding issue.

 

[FordMan4X4]

With radio and rear defroster on and vehicle running I unplugged one at a time each side of the rear defroster and static stopped each time. I will try and find time tomorrow to disconnect fuses.
FCIM and MS-CAN? I worked in a Ford dealer in the 70s and at Ford from 70s thru the early 2000s not strong on acronyms

 

[RangerBill]

With radio and rear defroster on and vehicle running I unplugged one at a time each side of the rear defroster and static stopped each time. I will try and find time tomorrow to disconnect fuses.
FCIM and MS-CAN? I worked in a Ford dealer in the 70s and at Ford from 70s thru the early 2000s not strong on acronyms

No need to remove fuses as you have isolated the static being caused by the rear defroster grid or connections to it. You will have to carefully examine the grid lines for issues. You could use an ohmmeter to measure resistance of each grid line and compare the readings to other grids.

If you have an infrared digital thermometer, you might try pointing it and following along each grid to look for differences in the reading to try to find a bad connection.

 

[airline tech]

With radio and rear defroster on and vehicle running I unplugged one at a time each side of the rear defroster and static stopped each time. I will try and find time tomorrow to disconnect fuses.
FCIM and MS-CAN? I worked in a Ford dealer in the 70s and at Ford from 70s thru the early 2000s not strong on acronyms

FCIM - Front Controls Interface Module - It's the front panel that has the (Rear Defrost) Button
It's not an actual switch - it's a data bus (MS-CAN) Medium Speed (Controller Area Network)
The switch sends a data pulse on the network - that it is pressed
When the switch is pulsed, it applies the Ground for the (Coil Side) of the relay to allow the relay to close.

Out of curiosity - You may still try pulling the fuse for the mirrors - since its easy access and see if you get the same outcome as disconnecting the (Power & Ground) leads from the window

Rear Window: Power Runs Through the Grid to Ground
C402A = Power (Drivers Side)
C402B = Ground (Passenger Side)

Check for Power and Ground @ Connectors when disconnected
Key On: & Switch (On) Check Power on C402A (Battery Voltage) Same as Measured at the Battery when running
Key Off: Ohms Scale (C402B to Body Ground) Should be reading 3 Ohms or less
I am looking for a abnormal voltage drop or a bad ground (with these tests)
I suspect it's a bad ground
Alternately you can disconnect the Ground Connector C402B and use a Jumper Wire and connect it to the (Glass) Connector and jumper the wire to a GOOD BODY GROUND and see if the issue stops- this will verify the Power is good and the glass is good, and the issue is on the ground side of the circuit.
Before we condemn the glass itself

If you get high resistance reading from C402B, then we need to move to C3049 (Pin #21)
Check for corrosion (dirty connection)

For the window Grid (Check)
It's easier for you to watch a video than explain it
Note: Starting at the power side the voltage should be dropping (if using a meter) as you move the lead across the glass towards ground (Example Midpoint = Approx 6 Volts)
Voltage Drop (Power being used)
If using a test light - the light will get dimmer
If you get to a point where you are reading (0) volts and you are not at the end of the line (It's broken at the point)

Ref: Video for understanding

how to check rear window heat defrost grids for power and ground - Google Search

 

[FordMan4X4]

I did not take a full dive into this.
I am looking for close proximity pins in the connectors or harness runs
A suspect connector to check for bad / dirty connection.
My HUNCH is it's on the heated mirror side of the circuit, using the logic that the heated mirrors run with the speaker wires.

You may also note: Is it reception static (antenna) or speaker and if speaker (ALL or Specific)
To help in pinpointing down which harness run its in.

A suspect connector to check for bad / dirty connection
Pin #8 = Left Heated Mirror - Heat Power
Pins 1 &2 = LF Door Speaker

Check Pin #8 - ensure its clean and secure in the cavity

 

[FordMan4X4]

I had time to check the grids on the rear defroster today and they checked out good using a multi meter. While locating fuse 37 I was timed out on defroster for the second time and when I switched back on I did not hear the static. Tried a couple more times and nothing. Waited a couple hours and checked again still no static. Check again tomorrow. Thanks for all of your input so far.

 

[airline tech]

I had time to check the grids on the rear defroster today and they checked out good using a multi meter. While locating fuse 37 I was timed out on defroster for the second time and when I switched back on I did not hear the static. Tried a couple more times and nothing. Waited a couple hours and checked again still no static. Check again tomorrow. Thanks for all of your input so far.

So, the meter test @ the window fixed the issue?
What specific actions did you do here?
or
You pulled and reinstalled Fuse #37 and it fixed the issue?

 

[FordMan4X4]

I was strictly working at the window. At first I was getting inconsistent readings. I didn't want to scrap any of the grid. So during the 3 attempts the defroster timed out twice. The third attempt at turning it on the static was gone. Checked it 3 more times during the evening and no static. The final attempt I was set up to try the 12 volt test light and tried it in a few places. I am sure it will pop up again. I did pull the fuse after checking it later in the evening.

 

[RangerBill]

I was strictly working at the window. At first I was getting inconsistent readings. I didn't want to scrap any of the grid. So during the 3 attempts the defroster timed out twice. The third attempt at turning it on the static was gone. Checked it 3 more times during the evening and no static. The final attempt I was set up to try the 12 volt test light and tried it in a few places. I am sure it will pop up again. I did pull the fuse after checking it later in the evening.

It sounds like there was either a bad connection at one of the 2 power leads to the window or a slight crack in one of the grid lines. Either case could cause a small arc that would create static noise in the radio.

Sponsored