Need help with 69 Charger Instrument cluster problem.

[vanceboy]

So I took the instrument cluster out of my 1969 Charger to replace the incandescent light bulbs with LEDs.

I hooked back up all of the wires and reinstalled the dash.

Everything worked before I started the project.

Now, everything works except the oil pressure gauge and the water temp gauge.

Question, are those two gauges connected by the 4 prong straight connector that plugs directly into the back of the PCB on the instrument cluster?

And if they are, is it possible I got the connecter 180 degrees backwards? The fuel gauge does work.

Any other ideas of why those two gauges aren't working? Again, they were working before I started.

Thanks.

 

[70 sublime]

I think the 4 prongs have an odd ball spacing so the plug will only line up one way

When you pulled it apart you could have pulled the 2 posts out of the circuit board enough that they are no longer making good connections

 

[vanceboy]

I checked the 4 prongs after I took the dash out. They were all solid and not wiggly.

 

[vanceboy]

By the way, I didn't mention it but the ammeter also works.

 

[davek]

Fuse?

 

[70 sublime]

The ammeter has its own wires
The gas oil and temp are the only thing the 4 prongs run so if one is working you have power

 

[70 sublime]

The oil and water wires go through the firewall while the gas gauge goes into the kick panel at the side
Any chance you yanked on the fire wall plug ?

 

[pnora]

So I took the instrument cluster out of my 1969 Charger to replace the incandescent light bulbs with LEDs.

I hooked back up all of the wires and reinstalled the dash.

Everything worked before I started the project.

Now, everything works except the oil pressure gauge and the water temp gauge.

Question, are those two gauges connected by the 4 prong straight connector that plugs directly into the back of the PCB on the instrument cluster?

And if they are, is it possible I got the connecter 180 degrees backwards? The fuel gauge does work.

Any other ideas of why those two gauges aren't working? Again, they were working before I started.

Thanks.

That plug is 5 pins.

 

[vanceboy]

That plug is 5 pins.

Yes, I realized that after I wrote it. Sorry

 

[vanceboy]

The oil and water wires go through the firewall while the gas gauge goes into the kick panel at the side
Any chance you yanked on the fire wall plug ?

I doubt it but Ill check. Thanks

 

[pnora]

Yes, I realized that after I wrote it. Sorry

Make sure you did not break the pins out of the board or broke their connection. Very common failure. Also tighten all the nuts that connect the gauges to the panel. With one gauge working that means the limiter is working.

 

[vanceboy]

checked the firewall plug, looks fine

 

[Billccm]

These circuit boards are phenolic and can develop hairline cracks and the contact pins are just pressfit without solder, which could go high resistance easily.

Thinking out loud two gauges have failed. The common connection to these two gauges is 5V power and ground. Try to visually inspect the traces between the ground screw and those two gauges. Then do the same with the trace from the IVR to these two gauges. The trace for 5V probably runs across the board and is susceptible to cracks.

If you can solder these are simple to repair. If you can't I'd be happy to look at it for you at no charge.

 

[vanceboy]

These circuit boards are phenolic and can develop hairline cracks and the contact pins are just pressfit without solder, which could go high resistance easily.

Thinking out loud two gauges have failed. The common connection to these two gauges is 5V power and ground. Try to visually inspect the traces between the ground screw and those two gauges. Then do the same with the trace from the IVR to these two gauges. The trace for 5V probably runs across the board and is susceptible to cracks.

If you can solder these are simple to repair. If you can't I'd be happy to look at it for you at no charge.

Yes, I agree the common denominator between these two gauges has to be the connector, pins or circuit board traces. I thought I was careful with it but maybe not careful enough. I will pull the dash again tomorrow and check these things out.

 

[vanceboy]

There it is, burnt circuit trace. Now my question is, what caused this?

I installed leds in the dash. Too much voltage? I thought this mod was supposed to work. Has anyone else done this?

 

[pnora]

There it is, burnt circuit trace. Now my question is, what caused this?

I installed leds in the dash. Too much voltage? I thought this mod was supposed to work. Has anyone else done this?

You somehow grounded a circuit out. LED or regular lighting has nothing to do with the failure.

 

[vanceboy]

Before and after.

Now I'm hesitant to reassemble because I'm not sure there is a short somewhere.

 

[BLK 68 R/T]

Did you maybe pinch a wire when you put the cluster back in after adding the leds?

 

[Billccm]

I'm not a fan of the old mechanical IVR. The contacts can stick and cause damage. You can also eliminate that condenser when you upgrade the IVR.
MOPAR Products

 

[Triplegreen500]

I put LEDs in my '70 cluster, zero issues. Your problems aren't from the bulb swap.