01 ranger showing ground in fuse panels

[87linclsc]

I've never been very good with electrical. The noticable symptoms are... no radio, no right front side running light, no left front turn signal, and the blower motor is intermittent. All these problems, with exception of the marker light started at the same time a couple weeks ago.

Ive checked the fuses and the only one that was blown was the 20 amp fuse in 29 (radio) in the interior. I replaced it and the radio worked until i turned the ignition off. It's still hot & hasn't blown again. So I've used a probe on the panels in the cab and under the hood and decided i should get a new probe because i couldn't believe what it was showing...

Here's what i got showing connection to ground. The rest are hot...

With the motor running

Interior panel: 3, 7, 24, 28, 33
Engine bay: 30, 43 (both of these show hot when the headlights, which work fine, are on)

With the motor off

Interior panel: 2, 3, 7, 14, 16, 19, 20, 33
24 & 28 show nothing
Engine bay: 44, 30 & 43 (same as running)

What's throwing me off is none of them are blowing... the truck is almost 20 yrs old and has 170k on it, so i can accept the blower motor being unrelated. I've checked all exposed wiring, short of pulling the dash... no breaks. I'm sorry if this is on here already, but I've searched all over. Before i start pulling the truck apart i figured I'd see if it was something stupid like my fuse block being bad or something.

Thanks

 

[87linclsc]

Sorry, it's an 01, extended cab, 4.0, auto, 4x4. I put in an aftermarket head unit, speakers, & sub about 4 months ago. No issues until a couple weeks ago.

 

[snoranger]

It’s not unusual to see ground on a circuit that isn’t powered at the time.
Look at a simple light circuit:

Battery + —— fuse ———— bulb ————— battery -

If you remove the battery + , you will see battery- at the fuse because it’s still attached to bat- through the bulb.

 

[adsm08]

When you see a ground connection on a dumb light or a PowerProbe (especially a PowerProbe) at a fuse it is because the probe is sensitive enough to see the ground connection through the component the fuse powers, if the circuit is not turned on.

Ford uses switched powers and fuses go between switches and loads, so with the switch in the off position the entire circuit between the fuse and the ground is still hooked up. This is why your probe is showing ground at the fuse. Things turning off is also why you have more of them with the engine off.

 

[87linclsc]

Ok... with the radio harness unplugged, the constant feed is showing ground, not hot. Do i treat it like a fault and chase it down? Why isn't it causing a drain? Why isn't the fuse blowing? It is the correct size fuse. How do i proceed from here?

 

[Uncle Gump]

Do you have wire schematics for the truck?

If not... you should invest.

The Tech Library has some radio schematics for a 2001 you can have a look at...

Ford Ranger Wiring Diagrams - The Ranger Station

DISCLAIMER: Activities and vehicle modifications appearing or described at The Ranger Station and it’s pages may be potentially dangerous. We do not endorse any such activity for others or recommend it to any particular person – we simply describe … Continued

www.therangerstation.com

 

[ericbphoto]

Ok... with the radio harness unplugged, the constant feed is showing ground, not hot. Do i treat it like a fault and chase it down? Why isn't it causing a drain? Why isn't the fuse blowing? It is the correct size fuse. How do i proceed from here?

Does it truly have continuity to ground? Or is it just not powered? There is a difference.

Either way, if you are really looking at the constant feed, it should have battery voltage. If not, then yes there is a problem that must be found and corrected.