Datsun 620 Cluster Wiring Issues

[H3nleY]

Hello again!

 

Okay, so my cluster lights and gauges randomly stopped working after a rainy night. I thought it might have been corrosion on the bed to cab harness (because it rains in my truck lol) so I rewired them with spade connectors but to no avail.

 

The taillights, headlights, and marker lights work just fine.

 

What wire powers the cluster so I can specifically test that one for corrosion? If I'm looking at my diagram right, it should be pin #8/yellow-red wire?

 

Thanks!

Edited May 3 by H3nleY

[datzenmike]

Power from the light switch into the gauges is a Green?blue wire and it's the #4 pin on the gauge cluster. The illumination control (dimmer knob) provides the ground on the #2 pin on the Green/Black wire. 

 

Could be the dimmer switch. Find the Green black wire on the dimmer and ground it and the lights should come on. If they do the dimmer is at fault. If not then the problem is in the gauges wiring. Try unplugging the 12 pin connector in the back of the gauge cluster and plugging it back in. This will clean and seat the contacts.

[H3nleY]

1 hour ago, datzenmike said:

Power from the light switch into the gauges is a Green?blue wire and it's the #4 pin on the gauge cluster. The illumination control (dimmer knob) provides the ground on the #2 pin on the Green/Black wire. 

 

Could be the dimmer switch. Find the Green black wire on the dimmer and ground it and the lights should come on. If they do the dimmer is at fault. If not then the problem is in the gauges wiring. Try unplugging the 12 pin connector in the back of the gauge cluster and plugging it back in. This will clean and seat the contacts.

Thanks Mike! Which wire gives power to indicators like the Charge light when the ignition is on? That stopped coming on when I turn the key as well 

Edited May 3 by H3nleY

[datzenmike]

The charge light is connected to the battery on one side and the alternator on the other. When the ignition is turned on power flows from the battery into the alternator to ground. When running and charging there is 12v on both sides of the lamp and everything is equal and lamp does not light.

 

 What about the oil pressure and the brake warning light? Do they come on before starting? All three are powered from the same source.

[H3nleY]

36 minutes ago, datzenmike said:

The charge light is connected to the battery on one side and the alternator on the other. When the ignition is turned on power flows from the battery into the alternator to ground. When running and charging there is 12v on both sides of the lamp and everything is equal and lamp does not light.

 

 What about the oil pressure and the brake warning light? Do they come on before starting? All three are powered from the same source.

The oil pressure and brake warning light never came on before. I know the reason for the latter is that the handbrake doesn't work. The charge light is the only one that worked

 

I'm pretty sure something is wrong with the cluster wiring because both the charge light and fuel gauge stopped working at the same time.

[datzenmike]

The brake light lights with the ignition on, only to show that the bulb works. There is a pressure switch in the hydraulic system that alerts the driver with that red light if there is a failure in one of the two circuits. It also lights if the hand brake is left on. Get your hand brake working, you life and others may depend on it.

 

Oil pressure is vital to the engine. The oil pressure sender is just forward and above the starter and to the rear of the oil filter. Pull the Yellow/Black wire off and hold against the block with the ignition on. The red light should come on. If it does, the sender is bad, replace it.

 

Fuel Gauge.  At the tank ground the Yellow wire with the ignition on. The gauge should read FULL.

1/ If it does check the Black wire near it is good. Make a ground wire and touch the Black wire terminal. If the gauge begins to work then the Black ground wire is bad. If no change the sender in the tank is bad.

2/ If it still does not read then the Yellow wiring forward to the gauge or the gauge may be bad.

 

[H3nleY]

2 hours ago, datzenmike said:

The brake light lights with the ignition on, only to show that the bulb works. There is a pressure switch in the hydraulic system that alerts the driver with that red light if there is a failure in one of the two circuits. It also lights if the hand brake is left on. Get your hand brake working, you life and others may depend on it.

 

Oil pressure is vital to the engine. The oil pressure sender is just forward and above the starter and to the rear of the oil filter. Pull the Yellow/Black wire off and hold against the block with the ignition on. The red light should come on. If it does, the sender is bad, replace it.

 

Fuel Gauge.  At the tank ground the Yellow wire with the ignition on. The gauge should read FULL.

1/ If it does check the Black wire near it is good. Make a ground wire and touch the Black wire terminal. If the gauge begins to work then the Black ground wire is bad. If no change the sender in the tank is bad.

2/ If it still does not read then the Yellow wiring forward to the gauge or the gauge may be bad.

 

I have an auxiliary oil pressure gauge and a handbrake cable on order don't worry

 

To me it doesn't make sense that all of the cluster indicators would go out at once (charge light, fuel gauge, and the dash lights) which is why I'm suspecting something wrong in the actual cluster wiring (maybe the circle connector). 

 

Will take another look at the wiring and report back 

[H3nleY]

Hey! A bit late to post this but uh, embarrassingly enough the fuse had just blown. It's fixed now 🤣