Where is the FM radio ground located? A few years ago I had a touch screen radio put in place of the OEM radio. When it's picking up an analog signal it gets crackly like an AM station with engine noise. If the signal is digital, then it is fine. It sounds like a ground issue. Should it be grounded to a different spot?

Also, what is this ground in the back middle under the hood? Should it be touching the body, or should I unbolt it and move it away?

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20171021_121256.jpg (94.7 KB, 18 views)

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2001 Ford Ranger XLT, 2.5L engine, single cab, manual transmission, RWD

There should be 2 pins on the factory connector that is ground. See the attached wiring diagram. Also, it looks like the ground in your photo is okay. You can test it for a voltage drop by hooking a multi-meter to each end of the wire (or ground strap) and applying a load (running engine, radio, lights or whatever is required by that circuit). Ideal drop should be 0.00 volts.

Attached Files

2001 2.5 Ground distribution 2.pdf (85.2 KB, 11 views)

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Rick Large
Mesa AZ
'99 Ex-Ranger 2wd XLT 5.0, Explorer V8 and auto transmission swap, floor shifter from Nissan Altima Parts, aluminum radiator & electric fan, OBX headers, 3" custom exhaust, explorer roof rack, 2006 mirrors, cut front 60/40 seat to buckets, 4 in lift spindles up front and shackles in back

What you're describing sounds more like interference, not a ground plane issue. The newer head units are a bit more sensitive in general for better reasons but its a bit of a double edge sword. Must be a pretty important radio station for one to start chasing down ghostly ground loops (?).

The ground strap on the firewall connects to the back of the head/block to include the firewall withe the rest of the earthing of the chassis so that windshield wiper motor doesnt back feed or radiate EMF noise. No need to move it nor would I remove it. When i was upgrading all of the vehicle grounds from the battery system in my 93', I had left that temporarily disconnected, radio is always on, and I seem to always bump my leg into the stupid multifunction switch that operates the wipers. The noise introduced sounded like a temporary alternator whine until I replaced/reconnected it the following day with the upgraded wiring; Needless to say, noise gone.

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It does it on all stations, not just one.

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2001 Ford Ranger XLT, 2.5L engine, single cab, manual transmission, RWD

That's a great idea......disconnect the ground from the engine block to the chassis. It should be against the law for someone with a double digit IQ to work on a vehicle.

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Your reading comprehension skills are lacking. The ground is touching the chassis and I asked if I should unbolt it and move it away (therefore rebolting it).

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2001 Ford Ranger XLT, 2.5L engine, single cab, manual transmission, RWD

before I suggest a filter of sorts, cause usually that throws one issue out the window but creates additional ones. I would take a normal automotive wire, say 18ga.. attach it to the ground wire. turn the radio function on and touch it to different parts of the [RADIO] chassis and see if the noise continues, lessens, or goes away. There very well could be a bad solder joint on a board or depending on brand, just poorly designed in the name of COGS thats not fully grounded other than through circuitry and its causing a possible back-feed or EMF noise..

Not to point out the obvious here, I know Dvrich loves a great argument but. the "ground" braided cable you are describing as touching the chassis? The Chassis is ground itself, both points are connected through the braided cable itself on both the engine ground side which is connected through the block at one of the starter bolts to the frame through a stripped back portion of the insulator with a grounding tab crimped on to the Battery negative terminal itself which also grounds from that same point to the header panel above the left headlight just left of the radiator/Ac line and to under the fuse box area if I recall.

In essence, its a moot thought.

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