Author Topic: Instrument Cluster Wiring Harness  (Read 132 times)

wtatoy

  • Active Forum Member
  • *
  • Posts: 63
Instrument Cluster Wiring Harness
« on: May 14, 2019, 07:04:36 AM »
Are all the coloured wires in the harness (turn signal, brake warning, high beam) all 12 V, ie: that wire + ground would be able to 'turn on' an LED light

There's 12V power on the harness, what's that for on the instrument cluster harness?

Are the coloured wires power?

The 12V power on the harness is confusing me.

Can anyone clarify?

b_hill_86

  • Active Forum Member
  • *
  • Posts: 228
Re: Instrument Cluster Wiring Harness
« Reply #1 on: May 14, 2019, 07:43:24 AM »
What year is your car and what are you trying to do? That may help get you more clear answers
-Brian-

1977 Trans Am 400 4 speed

wtatoy

  • Active Forum Member
  • *
  • Posts: 63
Re: Instrument Cluster Wiring Harness
« Reply #2 on: May 14, 2019, 07:54:49 AM »
Thanks

It's a 1978 Firebird - warning lights, speedo, no gauges

I bought SpeedHut gauges - didn't want the warning light model - looks to cluttered to me.

I added the SpeedHut sensors for the gauges, no issues.

I want to add LED lights to replace the warning lights I lost - off the original instrument panel.

I want an LED for the Oil, Temp, Amps and Brake.  I know which wires are associated with each, but the instrument wiring harness has 12V power going into it - that confuses me - I thought the individual wires were 12 V + with the ground being the -

If I hook up the Oil wire to the + of the LED and - to ground will the Oil sensor activate the LED?

Thanks

MIke

firebirdparts

  • Jedi Council
  • Oracle Forum Member
  • *
  • Posts: 18368
Re: Instrument Cluster Wiring Harness
« Reply #3 on: May 14, 2019, 09:04:32 AM »
There's only a couple of wires to the instrument panel that are sources of power.  One runs the clock, and it's hot all the time (orange).  If you want a switched one, those are pink with a black stripe.  There is one running to the cluster which powers the warning lamps.  It's hot when the ignition switch is on.  All those warning lamps are ground switched.

Illumination is gray and that one can be dimmed.

The rest of them, stay away from 'em.

Here maybe is the source of the confusion:  When a circuit is open, everything in that circuit up to the open spot looks like it's lit up with the full 12 volts.  All that stuff is ground switched, so it's all hot, but it is not all sources of power.
« Last Edit: May 14, 2019, 09:09:31 AM by firebirdparts »
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

wtatoy

  • Active Forum Member
  • *
  • Posts: 63
Re: Instrument Cluster Wiring Harness
« Reply #4 on: May 14, 2019, 10:07:13 AM »
Thanks - I guess the ground switching is what makes what I want to do not possible.

So basically the instrument panel is 'hot' and the colored wires close the ground side of the circuit to illuminate the lights?







There's only a couple of wires to the instrument panel that are sources of power.  One runs the clock, and it's hot all the time (orange).  If you want a switched one, those are pink with a black stripe.  There is one running to the cluster which powers the warning lamps.  It's hot when the ignition switch is on.  All those warning lamps are ground switched.

Illumination is gray and that one can be dimmed.

The rest of them, stay away from 'em.

Here maybe is the source of the confusion:  When a circuit is open, everything in that circuit up to the open spot looks like it's lit up with the full 12 volts.  All that stuff is ground switched, so it's all hot, but it is not all sources of power.

Re: Instrument Cluster Wiring Harness
« Reply #4 on: May 14, 2019, 10:07:13 AM »

firebirdparts

  • Jedi Council
  • Oracle Forum Member
  • *
  • Posts: 18368
Re: Instrument Cluster Wiring Harness
« Reply #5 on: May 14, 2019, 01:53:34 PM »
That's correct for all those warning lights.

For the turn signals and high beam indicators, it's the other way around.  That is what the black ground wire is for, that and the fuel gauge and maybe a clock if you had one.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

wtatoy

  • Active Forum Member
  • *
  • Posts: 63
Re: Instrument Cluster Wiring Harness
« Reply #6 on: May 14, 2019, 02:00:24 PM »
Thanks - just to clarify, I can run the turn signals (LED)using the appropriate wires and the ground then.

On other questions, if you happen to know - the fuel gauge says position 19 but there is no position 19 on the main harness - is there another harness, someone mentioned one near the lighter?

would you happen to know, the fuel gauge is the last problem I'm having

thanks again



That's correct for all those warning lights.

For the turn signals and high beam indicators, it's the other way around.  That is what the black ground wire is for, that and the fuel gauge and maybe a clock if you had one.

firebirdparts

  • Jedi Council
  • Oracle Forum Member
  • *
  • Posts: 18368
Re: Instrument Cluster Wiring Harness
« Reply #7 on: May 14, 2019, 02:23:41 PM »
The wires are already there to do high beam and turn signal, yes.  You just need to hook up to your LED.

The Fuel gauge location is different for gauges vs. non-guages.  On your car, you should have a sender wire going from the fuel gauge on your original main cluster plug and you don't have that side cluster plug.  That is if you are using the original wiring harness.  The fuel gauge sender is pink, no stripe.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

wtatoy

  • Active Forum Member
  • *
  • Posts: 63
Re: Instrument Cluster Wiring Harness
« Reply #8 on: May 14, 2019, 02:51:08 PM »
thanks will give it a try

really appreciate the help

Mike

The wires are already there to do high beam and turn signal, yes.  You just need to hook up to your LED.

The Fuel gauge location is different for gauges vs. non-guages.  On your car, you should have a sender wire going from the fuel gauge on your original main cluster plug and you don't have that side cluster plug.  That is if you are using the original wiring harness.  The fuel gauge sender is pink, no stripe.

Re: Instrument Cluster Wiring Harness
« Reply #8 on: May 14, 2019, 02:51:08 PM »
You can help support TAC!