Courtesy lights stay on & Fuel guage not working on my 65.

[Fred Y.]

Well I just had my instrument cluster restored & I put it back in. Once completed & steering column back in & plugged back up my courtesy lights wont turn off & I have no Fuel gauge. buried at zero ( I have 1/4 tank)

I went through all the test procedures outlined years ago by John Hinkley & found no juice at the fuel gauge plug. Then in his article he mentioned something about a "green wire" coming from the front engine bay to complete a circuit. I ran a ground wire from the ground screw on my alternator into the cockpit & then used that as my ground and then touched the pink wire on my fuel gauge and I had Juice. BTW, I did all necessary tests on my sender & all was AOK ---Juice in----OHMs ok when I moved the float.

Door plungers were checked---Knob for interior lights/Headlights off---wiggled the engine bay fuse block plugs---but did not remove to clean --"YET". Amp gauge works ok. Dash lights behind cluster all dim & brighten as they should. Headlights work fine.

It's been MANY months since I took this all apart, but I'm 100% certain that my courtesy lights shut off prior to the rebuild & 75% sure my fuel gauge worked as well. Now I DID have the rear harness unplugged while cluster was out but that's plugged back in now.

99.9% a ground , BUT WHERE ?? All I can say is that the switch for the headlights with rheostat was squeaking so I sprayed some WD on it, but this AM I removed with contact cleaner in case that was a mistake.

Sure would appreciate some help -----Thanks very much.

[James W.]

Re: Courtesy lights stay on & Fuel guage not working on my 65.

I beleive if you read John Hinckley's Fuel gauge testing artical again he mentions everything fed at the rear wiring harness grounds through the single ground wire attached under the instrument cluster. I would go back and check the rear wiring harness connecrion. Be sure it is locked together tightly.

James

[Richard M.]

Re: Courtesy lights stay on & Fuel guage not working on my 65.

Fred,

The ground for the cluster is a black wire(female spade in a plastic housing), which connects to a brass flag terminal at the top rear of the cluster. Is that connected?

Courtesy Lights:

If always on, 2 possibilities.
1- Door switches. Have a helper push pass side in while you push driver side in. Result?
It's likely one of the 2 door switches not opening, or the white wire at either fell off the switch and touching ground metal in the birdcage.

2- Headlamp switch rotation. If full CCW, this connects cluster ground to White wire on HL Switch, activating courtesy lamps.(See notes below)

BTW, Never spray any flammable liquid on the HL Switch rheostat. It could catch fire. They all can squeak. It's metal to metal(tungsten wire). It can exceed 300* F.

Lamp +power is constant, Orange circuit. Ground(White) turns them on, either door switch to frame ground or HL Switch.

Fuel guage(meter):

Need more data. I'm confused.

No power at Fuel gauge(meter) Pink, but you have power at Sender Pink? This is the same circuit, fed from Ign Switch, to fuse panel GUAGES fuse.

So the only explanation is, based on your explanation, is a open in the harness Pink wire...to the Fuel guage(meter). But... I doubt this because I this it's just a test meter malfunction, as I'm thinking it simply wasn't grounded when testing the Pink, correct?

Where is your test meter ground lead attached? The Cluster? Are you saying when you ground the cluster from the Alt ground, now you get voltage at Fuel meter Pink? What about TEMP Guage Pink? It's the same circuit.

Do Dash Lamps work? Does the Wiper motor work? If so, the Cluster is properly grounded.

Rich
P.S. Notes: HL Switch operation(Link to full thread HERE)

Rotating knob positions are as follows:

Full CW - Dash lamps Off
In this position the rotating wheel outer contactor moves away from the rheostat wire on to the porcelain, opening the circuit.


Full CCW(before detent click) - Dash lamps Full bright
In this position the rotating wheel contactor moves away from the rheostat wire on to the rivet supplying max voltage to the lamps.


Full CCW(after detent click) - Dash lamps Full bright, Courtesy lamps On
In this position, as above, the dash lamps are still full bright, and a separate copper contactor is closed onto the switch metal cover, activated by the plastic actuator tab pushing down on the copper. This connects cluster ground to the separate courtesy lamp circuit, turning them on.


Partial rotation CW/CCW - Dash lamps Dimmed CW, Brighter CCW
The rheostat is in the circuit varying voltage to the lamps.