Unknown Item and Gauge Problem

[bartman]

I've removed my dash to install a Vintage Air System and I'm currently in the process of reinstalling it. I have everything working except for my Oil Pressure and Water Temperature gauge. I also have a small electrical device that I don't understand.

The device is a small metal cylinder that had one bolt holding it to the inside of the dash. It has a light inside it for some reason and the light turns on when the other dash lights are turned on. It is connected to the lights and has one connection to the side of the cigarette lighter. I took a picture and put it in my gallery, but it's pending approval. I don't think this device is causing any problem, but I'm just curious as to its intended function.

On the gauge problem, I tried grounding the wires that connect to the sending units with no response from the gauge needles. I used a test light and it lights up when I do this with the key turned on. Either there's a connection that I missed when I reinstalled or there's a problem with the gauge. How can I test the gauge or the wires that connect to the gauge (can I just provide a power and ground and expect to see the needle move)?

[montoya_fan01]

you can "attach" the picture to this thread directly, instead of putting it in your gallery.

[260Zed]

The device is a small metal cylinder that had one bolt holding it to the inside of the dash. It has a light inside it for some reason and the light turns on when the other dash lights are turned on. It is connected to the lights and has one connection to the side of the cigarette lighter. I took a picture and put it in my gallery, but it's pending approval. I don't think this device is causing any problem, but I'm just curious as to its intended function.

I know what you mean. When I removed mine I spent a good 10mins looking at it thinking wtf? I believe it provides light into the cigarette "barrel" when the dash lights are turned on. When I looked it up in my FSM it showed a different setup with the bulb actually attached to the barrel. Not the separate cylinder. Must have been one of those small changeovers within the series.

Luke

[er34gtt2000jp]

Yeah,

That is the "fiber optical" light for the cig lighter.

I know the early 280z had one, not sure about the 240 though.

[EScanlon]

That is the "fiber optical" light for the cig lighter. ...

Exactly right.

Here's an explanation from last year:

... item is the Light Housing light source for the 4-Way Flasher Switch (Pull/Push Style) and the Cigar Lighter. The "odd" light bulb socket goes in there, and lights / dims with the normal dash illumination. The light to the 4-Way Flasher and the Cigar Lighter Housing is "sent" there via a Fiber Optic Cable. The FOC goes THROUGH the 4-Way Flasher STEM and then into the head of the Push/Pull Knob, on the Cigar Lighter it exits at a small hood that is attached to the side of the Cigar Lighter Body. It's a very nice subdued light effect.

HTH

E

[bartman]

Exactly right.

Here's an explanation from last year:

HTH

E

I thought it was some sort of light for the cigarette lighter, but although the device lights up the cigarette lighter doesn't. Maybe something's wrong with the fiber optic part. Mine also doesn't go through the hazard pull switch.

Any advice on how to determine where my problem is with my gauge? I would think I could put a current through it with a multimeter to determine if the gauge is working or not.

[EScanlon]

The Fiber Optic Light Housing usually has two FO Strands connected to it. I have seen it with just one, but I think that was the exception.

Look at the end of the FO Cable when the light is lighted. It won't be like a flashlight, but will cast a "glow" off the end of the cable. That's what illuminates the shell of the cigar lighter, and when it's fed through the Hazard Switch, the Green "Hazard" disk on the end of the knob.

If you do not have any of the FO Cable on that light, then you are missing pieces.

E

[EScanlon]

As far as your gauges, if I recall correctly, the gauges don't actually receive the signal from the sensors at the engine. The sensors are such that they change their resistance value based on temp or pressure, but I do not recall if the resistance goes up or down and from what initial value. It is the resistance to ground that either allows the gauge to deflect, or not deflect as much.

As a result I don't know if you were to apply 12v+ to the Yellow Red wire and grounded or contacted the negative wire of your power supply to the Yellow wire that you wouldn't fry the gauge (zero resistance).

The only way is for someone to check the resistance value of their sensors at off (cold) and at normal operating pressure/temperature. Then you could duplicate that resistance value and be able to test your gague.

Till then ....

E

[bartman]

Here's the pic of the device I mentioned that I guess is supposed to light the cigarette lighter:

I tested my gauge wiring by supplying power to one end and grounding the other end with a test light. The test light lit up, so I figured it must be hooked up correctly and the gauge was bad. I found one on eBay for $15.00 including shipping, plugged it in...and voila everything works.

Thanks for all the info.