Need Help, electrical gremlins

Gman1038

New Member
Apr 7, 2021
3
0
1
18
1038 E Lehi Rd
I have a 1998 4.6 Mustang GT Automatic. Randomly the headlights, dash lights, dome light, power mirrors, radio, and keyless entry will stop working. I checked all the fuses and none of them were blown. Then randomly it started working again. That following night I was driving and everything stopped working again for about an hour then started working again and so on and so on. I have checked all the grounds under the hood and they are all clean. It is fuses 16, 13, 12, 8, and 4 that randomly stop getting power, I checked with a fuse light checker and those ones are not getting power when everything stops working. But when it all turns back on, they all have power again. Does anybody have any ideas as to what is happening? Help Please!!
 
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Gman1038

New Member
Apr 7, 2021
3
0
1
18
1038 E Lehi Rd
When all that cuts off, do you still have voltage at the alternator?
Yes, the alternator still has voltage, I drove the car for an hour the other day when nothing was working and my voltage meter did not drop, and other electronics still work like the brake lights and turn signals.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,890
518
204
Houston Texas
Randomly the headlights, dash lights, dome light, power mirrors, radio, and keyless entry will stop working
IMO the key to your problem is the list of devices that stop working.

The head lights are unusual as they are on an "always on" circuit.

So what one thing does all of the above systems have in common? If this were my car I would be thinking "ground". Since the headlights are affected I would be thinking the main battery and radiator core support grounds.

Here's some more information that if followed will help trouble shoot most any bad electrical connection.


Howto perform charging system voltage drop test
 

hotcobra03

Active Member
Nov 29, 1999
969
4
39
poteet,tx
Agree with wmburns,


I had issues with the ground from battery to radiator support.

Looking at it didn't do anything
As in checking the ends to be tight and clean

Mine burned inside casing where you would never see

Imo, this ground is to small.

I used a normal size ground wire found a short wire in Walmart for riding mower

Another area I had issue.

Mine the main ground was ran to a stud on engine mount,

Here the stud snapped but didn't fall out of mount causing a intermittenting power issue ,