• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech

Major electrical prolems

  • Thread starter Thread starter Bosko5.0
  • Start date Start date Jan 25, 2007
Prev
  • 1
  • 2
First Prev 2 of 2

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 5, 2007
#21
  • Feb 5, 2007
  • #21
I just made some progress i just ran a wire from the batt. to the boo switch wire and the third brake light was on.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Feb 5, 2007
#22
  • Feb 5, 2007
  • #22
The BOO switch has constant power.
The TS flasher gets constant and accessory power............

If you have known good 12 volts into the BOO, ensure you have 12 volts out of the BOO when the switch is pressed.

The following assumes the brake pedal is pushed down:

At the MF switch, look at:
Red/lt grn wire going into the MF switch. It should have 12 volts.
Then look for 12 volts leaving the Or/Lt blue wire and the Lt Grn/Or wire.

For the flasher:

Purple/Org is hot with the key-on.
Red/white is hot at all times.
Blk is ground. Look for less than 5 ohms of resistance.
White/Red is the output of the flasher and goes to the MF switch.

Replacing the flasher relay for a known good one is a very good idea something weird shows up in testing it's wires.

At this point, the common element to the low-mount brake lights and the flasher issues is the MF still.

Good luck.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 6, 2007
#23
  • Feb 6, 2007
  • #23
well i just bought the mf switch brand new from a dealership yesterday tested ok, i'll retest it to make sure.

i am not getting any power to the boo, the INT LPS fuse in engine compartment is not getting any power so i guess thats why the boo isnt getting power.

and my flasher relay was making a ggrrrrrrrrrrrrrrrrrrrrrrrrrr noise no clicking when left blinker was on and no lights. the hazards only the front pass. comes on . I hate wiring

do you think i could run new wires from the battery all the way to the rear lights?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Feb 6, 2007
#24
  • Feb 6, 2007
  • #24
INT LPS feeds fuses 5 and 9 inside the car (headlight switch and the BOO and flasher relay).

If you don't have power going *INTO* the INT LPS fuse under the hood, I looked at the schematic and don't see any fusible links or anything else. It looks to get battery power. I have not taken an underhood fusebox apart but I'd have to wonder if the leg that carries power from the PDC stud (on the side of the underhood fusebox) to the individual fuse slots ended up breaking.

An appropriately sized (AWG) short jumper from the PDC stud to the fuse slot could probably make it functional again. It would be cool to know why it broke though.............

Good luck.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 6, 2007
#25
  • Feb 6, 2007
  • #25
axcualy it is a piece of metal that connects all the fuses together. very simple.

i dont think its broken but i'll see I'll post back today around 1-4pm i gots to be at work in 3 hours.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Feb 6, 2007
#26
  • Feb 6, 2007
  • #26
Bosko5.0 said:
axcualy it is a piece of metal that connects all the fuses together. very simple.

i dont think its broken but i'll see I'll post back today around 1-4pm i gots to be at work in 3 hours.
Click to expand...

Thanks for the info. It sure sounds like there's a bad connection in that metal grid thing then - you have power to the PDC but not to that fuse. It's nice when you have but a few inches of stuff to trace rather than a length of the car.

Good luck.
 
B

bmac50

New Member
Oct 18, 2006
123
0
0
Florida
Feb 6, 2007
#27
  • Feb 6, 2007
  • #27
I just went threw something every much like this, the alternator looked to be bad and the starter looked to be bad also. It ended up being the cables that are on the battery and go to half a dozen places. I had one because I was planning on replacing it anyway because of the age (12 years old in Florida). The garage wanted to replace the starter first and then the alternator if the started didn't fix it but I nixed that because I already had the cable so at the time that was my cheaper route. Problem fixed!!

If the car sat for an hour or so it would start but if you ran into 7-11 and back out the car would be dead. With the old cable the alternator would put out 70-75 amps thus cooking the new battery and with the new cable everything returned to normal. We (the three of us) it was a floating ground.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 6, 2007
#28
  • Feb 6, 2007
  • #28
well i replaced the flasher the noise is gone but the only lights that work are the front pass. hazard and the rear driver hazard. I have the next two days off hopefully i can solve this problem within the next two days. Iam also going to install my new alt tommorrow.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 8, 2007
#29
  • Feb 8, 2007
  • #29
well put the new alternator on and its still not charging And still no brake lights, but i do have power to the the ints lights fuse and i have power at the #9 fuse

on the regulator

A: 11.7v
s: 12.5V
i: 12.5V

BATTERY IS AT 12V

i checked the ignition switch and i have connutity in the: start, run, acc position but i have no connutity in the: off, and lock position

and also my battery light at the bottom of the cluster doesnt work even when the battery was at 8.5volts and my interior lights dont come on.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Feb 9, 2007
#30
  • Feb 9, 2007
  • #30
Refresh us about the brake light situation. How's the flasher (it shares #9 IIRC)?

If you only have the center brake light working, check I/O's at the MF switch again. If no brake lights work, check I/O's at the BOO again.

12.0 Volts (notice my use of a decimal locator) is pretty discharged for a battery.

The I circuit uses a resistor wired in parallel with the battery light, in the event that the light burns out (remember, a bulb is a resistor of sorts). This duplicity keeps the I circuit working in the event of bulb issues.

Now it seems to me that stator voltage should be 8-10 volts. Can anyone confirm this?

With the car turned off, you show 12.X volts on the charge stud on the back of the alternator? How does this figure compare to battery voltage? What are the results of the same test while the car is idling?
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 9, 2007
#31
  • Feb 9, 2007
  • #31
no brake lights at all unless i run a wire from battery to the boo,

if i turn the flashers on only the front pass. and the rear driver side work, same thing with turn signals

I took the cluster out and checked the bulb and resistor both good also checked wiring between input and out put on cluster

iam pretty sure the bolt on the back of the alt was the same as the battery.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Feb 19, 2007
#32
  • Feb 19, 2007
  • #32
Well i finally had the all the problems fixed it turns out that there was an open circuit in the driver kick panel where i ran all the wires into the door but i think the probem was already there and i just moved a wire and that caused it.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Feb 19, 2007
#33
  • Feb 19, 2007
  • #33
When you have multiple issues as I think your car did (the fusebox, the kick panel wiring, etc) it can be a real bear to track down the source of issues. I commend you for getting it all figuerd out. It just takes lots of time with the meter to do so.

Congrats!
 
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

G
  • Poll Poll
I got a free Mustang from Grandma
  • GrannysMustang
  • Mar 4, 2026
  • The Welcome Wagon
Replies
14
Views
343
The Welcome Wagon Mar 6, 2026
Realmongo
J
Emission problems
  • jls.zmmr
  • Feb 5, 2026
  • 1994 - 1995 Specific Tech
Replies
2
Views
213
1994 - 1995 Specific Tech Feb 7, 2026
AeroCoupe
Hard to start when engine is cold
  • 86_Capri
  • Mar 11, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
31
Views
761
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 21, 2026
86_Capri
T
What's it Worth? 2002 GT conv/auto
  • tonydetesta
  • Jan 7, 2026
  • What is it Worth?!?!?
Replies
3
Views
584
What is it Worth?!?!? Jan 21, 2026
Mustang5L5
A
Car is running bad
  • Anthony3511
  • Apr 30, 2025
  • SN95 V6 Mustang Tech
Replies
5
Views
346
SN95 V6 Mustang Tech Apr 30, 2025
89ripper
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?