Pennock's Fiero Forum
  Totally O/T
  Detected voltage under Fiero body. Wait, what?

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
Detected voltage under Fiero body. Wait, what? by CoolBlue87GT
Started on: 11-11-2025 12:28 PM
Replies: 14 (138 views)
Last post by: Stingray92 on 11-13-2025 09:57 PM
CoolBlue87GT
Member
Posts: 8529
From: Punta Gorda, Florida, USA
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 150
Rate this member

Report this Post11-11-2025 12:28 PM Click Here to See the Profile for CoolBlue87GTSend a Private Message to CoolBlue87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
IP: Logged
PFF
System Bot
maryjane
Member
Posts: 70139
From: Copperas Cove Texas
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 436
Rate this member

Report this Post11-11-2025 01:36 PM Click Here to See the Profile for maryjaneSend a Private Message to maryjaneEdit/Delete MessageReply w/QuoteDirect Link to This Post
You need to call an exorcist and quick!
IP: Logged
Raydar
Member
Posts: 41522
From: Carrollton GA. Out in the... country.
Registered: Oct 1999


Feedback score:    (13)
Leave feedback





Total ratings: 463
Rate this member

Report this Post11-11-2025 03:00 PM Click Here to See the Profile for RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's... ALIVE!

I'm guessing that it's picking up the wiring to the brake/tail lights, trunk light socket, and maybe the cruise control.
Doesn't the Fiero "switch ground" in order to turn stuff on? If so, there would be 12 volts on the circuit, even if nothing was active, at the moment.
IP: Logged
maryjane
Member
Posts: 70139
From: Copperas Cove Texas
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 436
Rate this member

Report this Post11-12-2025 06:35 PM Click Here to See the Profile for maryjaneSend a Private Message to maryjaneEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Raydar:

It's... ALIVE!

I'm guessing that it's picking up the wiring to the brake/tail lights, trunk light socket, and maybe the cruise control.
Doesn't the Fiero "switch ground" in order to turn stuff on? If so, there would be 12 volts on the circuit, even if nothing was active, at the moment.


There's quite a few 'hot at all times' wires in Fieros...well, at least a few that I remember.

IP: Logged
Stingray92
Member
Posts: 243
From: Indiana
Registered: Feb 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-12-2025 07:49 PM Click Here to See the Profile for Stingray92Send a Private Message to Stingray92Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'd have to double check but on this section of the car I thought only the rear defrost and tail lights ran this side.

Even so if voltage was present it would seem easy enough to check with a multi meter.

Just curious what the model/part number of the detector you used is? I'm not aware of a non contact detector for 12 volts DC or less.
IP: Logged
Patrick
Member
Posts: 39335
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post11-12-2025 08:30 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Raydar:

I'm guessing that it's picking up the wiring to the brake/tail lights, trunk light socket, and maybe the cruise control.


Doesn't the wiring harness for the taillights run down the passenger side of the rear clip?
IP: Logged
CoolBlue87GT
Member
Posts: 8529
From: Punta Gorda, Florida, USA
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 150
Rate this member

Report this Post11-12-2025 10:09 PM Click Here to See the Profile for CoolBlue87GTSend a Private Message to CoolBlue87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Stingray92:

I'd have to double check but on this section of the car I thought only the rear defrost and tail lights ran this side.

Even so if voltage was present it would seem easy enough to check with a multi meter.

Just curious what the model/part number of the detector you used is? I'm not aware of a non contact detector for 12 volts DC or less.


It's APV-600 Non-Contact voltage tester Mfg by AMES Instruments, Found this link : https://www.youtube.com/watch?v=8rxIKdYSy0M

It's for testing AC voltage - Having said that, you can see in my video, it's detecting something w/o the trickle charger on. not sure why, say's it's not for 12 V. It's a mystery.
IP: Logged
olejoedad
Member
Posts: 20026
From: Back home again in Indiana
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 201
Rate this member

Report this Post11-13-2025 08:17 AM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Doesn't the wiring harness for the taillights run down the passenger side of the rear clip?


The bulk of the taillight harness does, but the pigtail also extends around that corner of the rear to the side marker lamp, cruise control and rear trunk light.

IP: Logged
Stingray92
Member
Posts: 243
From: Indiana
Registered: Feb 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-13-2025 07:41 PM Click Here to See the Profile for Stingray92Send a Private Message to Stingray92Edit/Delete MessageReply w/QuoteDirect Link to This Post
I suspect your picking up some sort of interference from a light or maybe the power cord that looks to be under the car. I'm not sure what they use for the sensor probably a magnet or something along those lines.

It is odd, and for kicks I took mine and tried several areas with known 12v power and as expected nothing. However when I got within a couple inches of 120v power it picked it up.
IP: Logged
CoolBlue87GT
Member
Posts: 8529
From: Punta Gorda, Florida, USA
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 150
Rate this member

Report this Post11-13-2025 07:58 PM Click Here to See the Profile for CoolBlue87GTSend a Private Message to CoolBlue87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Stingray92:

I suspect your picking up some sort of interference from a light or maybe the power cord that looks to be under the car. I'm not sure what they use for the sensor probably a magnet or something along those lines.

It is odd, and for kicks I took mine and tried several areas with known 12v power and as expected nothing. However when I got within a couple inches of 120v power it picked it up.


Ding Ding Ding !!! - You were right !! I unplugged the extension cord, that was the reason it was finding voltage. Good eye. Boy that had me stumped. Thank you.
IP: Logged
Stingray92
Member
Posts: 243
From: Indiana
Registered: Feb 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-13-2025 08:07 PM Click Here to See the Profile for Stingray92Send a Private Message to Stingray92Edit/Delete MessageReply w/QuoteDirect Link to This Post
👍you're welcome
IP: Logged
PFF
System Bot
Patrick
Member
Posts: 39335
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post11-13-2025 08:35 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Stingray92:

However when I got within a couple inches of 120v power it picked it up.


"within a couple of inches ..." Makes sense.

 
quote
Originally posted by CoolBlue87GT:

Ding Ding Ding !!! - You were right !! I unplugged the extension cord, that was the reason it was finding voltage.


When you put your charger on the ground, your extension cord was at least a couple of feet(!) away. Makes no sense.

IP: Logged
CoolBlue87GT
Member
Posts: 8529
From: Punta Gorda, Florida, USA
Registered: Apr 2001


Feedback score: (4)
Leave feedback





Total ratings: 150
Rate this member

Report this Post11-13-2025 08:54 PM Click Here to See the Profile for CoolBlue87GTSend a Private Message to CoolBlue87GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:
When you put your charger on the ground, your extension cord was at least a couple of feet(!) away. Makes no sense.


If you look at 1:04 & 1:24 - 1:27 the cord is still right next to the wheel on the floor. That was close enough to allow the 120v signal to be picked up. Off camera, when Stingray92 suggested the cord was under the car, I checked, and unplugged the cord from power, that solved the mystery.

[This message has been edited by CoolBlue87GT (edited 11-13-2025).]

IP: Logged
Patrick
Member
Posts: 39335
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post11-13-2025 09:12 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by CoolBlue87GT:

If you look at 1:04 & 1:24 - 1:27 the cord is still right next to the wheel on the floor. That was close enough to allow the 120v signal to be picked up.


But yes, that's my point! Your voltage detector is at least a couple of feet away from the cord... certainly not "within a couple of inches" as Stingray had observed/commented.

IP: Logged
Stingray92
Member
Posts: 243
From: Indiana
Registered: Feb 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-13-2025 09:57 PM Click Here to See the Profile for Stingray92Send a Private Message to Stingray92Edit/Delete MessageReply w/QuoteDirect Link to This Post
Noise aka magnetic interference or in this case a 120v ac cord was in my opinion close enough to the car to pass through to the sensor.

In industrial control panels we must keep certain distances away between signal wires and 120 volt circuits.
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock