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instrument cluster wiring

 
jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/06/12 02:46 PM

I have a 1969 mustang w/302 i put a new printed circuit new voltage limiter and gauges don't work there is a wire that goes to wiper switch ignition switch and fuse block underdash and it gets very hot and to thr plug that goes in to the back of the speedo and gauges, does anyone know what causes the wire to get hot  ?  

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MustangMan
Moderator
Posts: 261
Joined: 08/11
Posted: 09/07/12 06:49 AM

Can you tell us the wire color of the wire that gets hot? It's most likely some sort of short, though usually a fuse or fusible link would protect it, unless someone has the wrong fuse value in the fuse box or it has been bypassed (the old tinfoil trick, etc.)

I'm not up on '69 dash wiring myself, but at least with the wire color we can trace it in a diagram or something.

HTH...
Mark
.  
Mark Houlahan
Brand Manager
Mustang Monthly Magazine

1965 FFR Roadster 427W/TKO-600 5-speed
1966 Mustang 289-4V/C4 Auto
1968 Mustang 4.6L Three-Valve/5R55S Auto
1990 Mustang 306/AOD
2002 Explorer Sport Trac 4.0L V-6/5R55 Auto
2005 F-150 4x2 4.2L V-6/4R70W Auto

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 09/07/12 09:58 AM

i am curious... if the printed circuit is properly centered over the connector opening... so its NOT touching 2 terminals of the connector at the same time...

also that you have not swapped in a different cluster... i see on my printed circuit diagrams that there are clusters with and without tach...

there also seem to be some with AMP meters.. some without amp meter but with an alternator light...

some have oil pressure and water temp gauges.. some have indicator lights...

i don't have a factory service manual that covers the slight differences in wiring..

please.... do not attempt to operate your car or hook the battery up until you have identified the issues..   you might have an electrical fire..  the one wire getting hot can cause damage deep inside the harness also...

can you post pictures of the back of your cluster... and several of the connector.. one looking in the end.. one from each side to allow wire colors to be identified by location..  

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jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/10/12 12:27 PM

the color of the wire that gets hot is a blue it comes directly from the plug that goes into the back of the cluster , it also goes to a rubber rectangular block and there are 2 other wires connected to the blue wire 1 is black with a green stripe  goes to the ignition and fuse panel and the other goes to the wiper switch and they don't get hot  

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 09/10/12 05:20 PM

my non ford wiring diagram shows a blue with a red stripe wire into the cluster plug..

its for the illumination circuit... spreads out all over the dash...

something is wrong..

please check your fuse in the box..

middle fuse on the side with 3 parallel fuses...      the wrong side has the middle fuse straight up instead of horizontal..

the fuse should be a  SFE 4

Sfe4bp

you still have a short someplace...  and thats going to be hard to find over the net.. its a hands on examination with an ohm meter...  with the power off... checking to see where there is too much resistance...  

did you switch clusters?????   did the car come with a cluster printed circuit that was burned...

there are differences in how the clusters are wired between the NON TACH clusters and the TACH clusters..  

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jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/10/12 07:28 PM

there is no tach the old circuit board was cracked from old age , i will have to find the short some how , thanks for all your help Ooo  

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 09/10/12 08:41 PM

now.. i feel bad... there is NO set location for a short in a wire...

you still did not say if you had a wiring diagram.... its easy.. yes.. NO???

everybody has to examine whole cars for a short...


example... i met a taxi driver with a short.. the wiring under the drivers seat had actually burned from the under dash area to the back of the car.. he replaced it.. it burned again..  he was going on a third try.. with really thick wire...   took me about 10 minutes to find that he had the tail light housing out.. and had pinched the wires under the tail light housing mounting screw..   after i found this.. he was able to complete repairs..

car repairs are not easy... i have been doing them for 32 years after a FULL year of tech school.. 8am till 3 pm..  and i am still learning new stuff daily.. new procedures.. new circuits..  new problems..  wiring is complex..  sorry.. mysterious electrons moving through a solid object..

another question.. DO you have a digital volt meter.. so you can use the continuity beeper to find your short..  you will have to study the circuit.. which is why you need a wiring diagram..  

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jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/11/12 04:01 AM

no wiring diagram and i do have a digital volt meter . i will have to trace the wiring from front to back for possible pinched wire or bad ground , i am restoring the car and i had all the interior out to bear metal and now i have to see if i did something when i put it back together  

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MustangMan
Moderator
Posts: 261
Joined: 08/11
Posted: 09/11/12 07:35 AM

I found a really grainy diagram via Google search and there's no blue wire listed on the dash connector for the gauge cluster. There IS a Violet wire that goes to a splice and then goes to the ign switch via Black/Green and the wiper switch via Orange/White.

This wire is not in the dash connector by itself though, it shows a Red/Yellow in the same terminal. The Violet wire is for the constant voltage regulator (CVR) that regulates the voltage to the dash gauges. Is this the small "rubber block" you are referring to? If you're not sure, the CVR is mounted on the cluster itself, or if your rubber block is mounted elsewhere that might help by letting us know its location.

Lastly, the only solid blue wires I found on the diagram (in my quick search) were one in the turn signal switch and one for the heater switch...

HTH...
Mark  
Mark Houlahan
Brand Manager
Mustang Monthly Magazine

1965 FFR Roadster 427W/TKO-600 5-speed
1966 Mustang 289-4V/C4 Auto
1968 Mustang 4.6L Three-Valve/5R55S Auto
1990 Mustang 306/AOD
2002 Explorer Sport Trac 4.0L V-6/5R55 Auto
2005 F-150 4x2 4.2L V-6/4R70W Auto

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 09/11/12 07:47 AM

i would carefully examine the printed circuit... figure out what each circuit does...   OHM them..  make sure that you have no shorts in the work you just did...

the top wire in this diagram to the cluster plug shows as a blue and red stripe.. for all the cluster illumination bulbs... controlled by the big ceramic rheostat on the headlight switch.. but after that fused by the 4 amp fuse ...
print this diagram several times... use colored high lighters to go over just the circuits effected..

i do have a better resolution copy of that..... click the messages to the left of where you log out at.

1969 Mustang Wiring Diagram  

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jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/12/12 04:03 AM

the wire could be violet and turned a blueish color because it got hot and it does go to the voltage limitor  

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 09/12/12 07:35 AM

this narrows it down..

now.. continue the examination of the cluster printed circuit..

the cluster voltage regulator has actually 3 terminals...

input 12 volts.. on the violet wire.. thats fed according to the wiring diagram from the same wire that feeds the turn signal flasher...

there should be a ground connection on it.. usually the mounting screw..

and the output wire... this goes to one stud of the gauges to power them..


if any of your gauges are shorted out...  or the wires from the engine or fuel tank is shorted directly to ground.. without any resistance.. there will be a massive amp surge.

so... you are going to need to OHM the output circuit from the cluster regulator..

its been so long.. i have forgotten what the temp and the fuel gauge should read when measured with an ohm meter..  they should not be a dead short ...    i think there is a cluster and gauge article in the tech or the how to sections... i will look around and see...

can you list which gauges you have???    

tachometer  y/n

fuel Y

temp Y/N

oil pressure Y/N  

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jstamand
New User
Posts: 6
Joined: 09/12
Posted: 09/12/12 11:04 AM

fuel          

temp

oil pressure

alternator

i also just found out my 4 way flashers don't work and i just put a new turn signal switch in the steering column i will have to trouble shoot that too , this never ends   LOL  

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waynep71222
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Posts: 455
Joined: 04/12
Posted: 09/12/12 01:21 PM

log in.. check messages to the left of where you log out at...  

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Sossong
New User
Posts: 6
Joined: 09/11
Posted: 09/17/12 08:37 AM

JSTAMAND- What did you end up doing to get this problem solved? I have the same problem with my 69 dash lights. I installed new wire harnesses throughout the car, a new voltage regulator for the instrument cluster, and new LED bulbs. I removed the old instrument cluster circuit card which was delaminated and "possibly" burned down low under the four mounting studs for the card. When I installed a brand new card, and wanted to check the LED lights, I smoke-checked the new card too in the same place under the four mounting studs and only on the one copper lead for the instrument cluster lighting.

Mad

Info:
Non tach car
No switched cluster
New headlight switch
I just plugged in the gas tank sending unit
Checked fuses

Does anyone know why there's a bulb (only one) in the circuit path prior to reaching the voltage regulator and my card burned between the connector and that bulb. All other bulbs are after the voltage regulator. (This question comes from Bill at EMCO, who makes the circuit card).  

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