Center console accessories lights flickering

chasingomas

New Member
Joined
Apr 26, 2024
Messages
16
Reaction score
3
Location
San Francisco, California
Hey y'all!

Finally got a car omg. I got a 1999 Mustang GT. There is an issue with the center console accessories lights (heat/ac, etc), they flicker while on. By flicker I mean, they aren't all the way bright, and modulate in brightness up and down, but never fully on or off. The dash doesn't do any of that lol hope that makes sense. The previous owner kind of shottily put in a new stereo and gps/music unit, not sure if that has anything to do with it, but probably, so I thought I'd mention it. Feel free to ask any questions or for any pictures. Thanks:)
 

ttocs

Forum's #1 poster
Joined
Oct 9, 2009
Messages
35,378
Reaction score
6,823
Location
Evansville Indiana
the fact they get brighter/dimmer is strange. It could be as simple as a harness with a broken clip that when it heats up creates some resistance, or else I am not sure what it could be. Start off by tracing the wiring and look for any bare spots or corrosion.
 

yezmar77

New Member
Joined
Mar 10, 2025
Messages
8
Reaction score
1
Funny, my 99 Cobra does similar stuff except w the dash, was driving along and noticed I had no odometer then couple minutes later it was back
 
OP
OP
C

chasingomas

New Member
Joined
Apr 26, 2024
Messages
16
Reaction score
3
Location
San Francisco, California
the fact they get brighter/dimmer is strange. It could be as simple as a harness with a broken clip that when it heats up creates some resistance, or else I am not sure what it could be. Start off by tracing the wiring and look for any bare spots or corrosion.
Awesome :) I'll do that. Thank you!
 

ttocs

Forum's #1 poster
Joined
Oct 9, 2009
Messages
35,378
Reaction score
6,823
Location
Evansville Indiana
your best bet to find it is to wait till it starts to do its show again and THEN you start tracing/dicking with the wiring. Any harness you see give a tug/pull/twist and see if it changes and more than likely you can narrow it down to one harness that when you give it some technical taps the lighting goes on/off/dim. I am tellin ya technical taps can be used in SO many areas to diagnose problems.
 

PNW Mike

New Member
Joined
Jul 26, 2023
Messages
42
Reaction score
21
If only stuff in the console is affected, that narrows down the possible harnesses and connections to check. I'd remove the console but leave the wires and switches laying there and see if you can reproduce the issue by moving stuff around. I don't recall if there is a ground connection under the console, if so, I'd check that.

Also check the radio and wiring behind it. Shoddy radio installs suck. Hopefully they used a proper adapter plug and didn't cut/splice directly into the dash harness.

This screams of a loose connection somewhere, or a bad t-tap or similar messing with the wiring.
 

ttocs

Forum's #1 poster
Joined
Oct 9, 2009
Messages
35,378
Reaction score
6,823
Location
Evansville Indiana
as he said there is one harness that feeds into the console from the radio are IIRC. Check the harness and make sure that the pins are clean/tight and try to measure the voltage if you can.
 

yezmar77

New Member
Joined
Mar 10, 2025
Messages
8
Reaction score
1
If only stuff in the console is affected, that narrows down the possible harnesses and connections to check. I'd remove the console but leave the wires and switches laying there and see if you can reproduce the issue by moving stuff around. I don't recall if there is a ground connection under the console, if so, I'd check that.

Also check the radio and wiring behind it. Shoddy radio installs suck. Hopefully they used a proper adapter plug and didn't cut/splice directly into the dash harness.

This screams of a loose connection somewhere, or a bad t-tap or similar messing with the wiring.
Now that you mention it, there was a CD changer setup in trunk of car attached to factory stereo…I totally just ripped it out, cut wires and taped em off, same for controller near the stereo, think I’ll do things right and back pull everything, see if that helps, Thank you!
 

ttocs

Forum's #1 poster
Joined
Oct 9, 2009
Messages
35,378
Reaction score
6,823
Location
Evansville Indiana
Sounds like an aftermaket fm modulated changer? If so I am not sure how it could cause this but it always helps to clean out old wiring your not using.
 

PNW Mike

New Member
Joined
Jul 26, 2023
Messages
42
Reaction score
21
There is a chance that the CD changer connects to the dash lights to light something up on/around the changer to be able to see it in the dark, or maybe even to do something as simple as light up a logo on it. I've seen weirder.

Even if it doesn't fix the issue, ripping out the unused CD changer wiring and capping off any unused connections properly (such as with heatshrink tuning or good fabric electrical tape, not the cheap vinyl electrical tape that gets sticky and falls off after a few years) is a good idea. if you want to leave the wiring there, make sure the wires are terminated, insulated properly, and routed safely. Are you really going to use a CD changer in the trunk these days? :)


Some things that I've learned from working on wiring in cars:

1) A bare wire that is intermittently touching ground, other wires, or even itself (aka, a loose connection in the wire) will cause all sorts of unwanted "entertainment" as you try and troubleshoot the issues.
2) Bad grounds cause downright bizzarre problems. If you are seeing crazy electrical issues and/or suspect your cars electrical system might have been cursed, check/clean/tighten your grounds first. Even the hard to find/reach ones - actually, especially the hard to reach ones, because Murphy.
3) People and shops that customize car wiring have been known to do some very, um, "creative" things.


I once diagnosed an intermittent stalling/no start to a fuel pump positive wire that had only one strand of wire still fully connected, the other strands in the wire were cut under the passenger's seat and would separate as the car shifted/moved around, causing the stall/no start. Cause? Someone very large had sat in the car, and the seat spring was stretched so far down that caught the harness through a gap in the carpet, and when they got up, it pinched that one wire and yanked it up, almost completely severing it. The wire was not fully cut, so voltage testing of the circuit showed good (12V at the pump, why won't it work?!?!?), it only showed up with resistance testing of that particular circuit. That was fun to track down.

Anything electronic in a car, such as the PCM, is notoriously sensitive to bad grounds. In some cases just 1V of added resistance can cause issues. I once helped a friend fix the cruise control in his wife's car - it turned out to be due to a loose ground wire at one of the tail lights. Yes, really.

Some of the worst aftermarket radio wiring I have ever seen was done by "professional" shops. There's a reason I do my own radio installs now - I got tired of ripping out other's work and redoing it. This is also why I own multiple crimpers and crimp dies for various terminal types, and have a bunch of spare terminals and connectors in a box in the garage. :)
 

cobrajeff96

Well-Known Member
Joined
Feb 1, 2022
Messages
2,346
Reaction score
2,464
Location
Germany
Check the two grounds at the bottom of the instrument panel, closer to passenger side, just to the left of where the blower fan is. Those two grounds serve almost the entirety of the dash. A flickering of those HVAC panel lights could indicate the circuit is overloaded due to someone else tapping into that circuit to provide power to something else, causing excessive voltage drop. Sounds like you got a little side project on your hands.
 

Latest posts

Forum statistics

Threads
78,343
Messages
1,525,834
Members
15,690
Latest member
happliye

Members online

No members online now.
Top