timd02

I am putting the interior of my 75 back together and am using a new center gauge bezel but the original gauges. When I hooked all the connectors back up(fuel,clock,oil press., etc) one of the studs at the bottom of the bezel touch the shifter console and sparks shot out. Is this normal? I did not see a ground on the back of the gauges anywhere. Needless to say, the battery is now disconnected and will be until I have the bezel in place.

Just seems odd to me that the speedo/tach gauges have a ground wire that attaches to the metal housing but the bezel gauges don't. A previous owner has been in there hooking up a radio so some grounds might be missing. If any of you have any pics of what the back side of the bezel should look like please post and as always, a big THANKS for your help.

timd02

Here are a couple of pics of what it looked like right before I took the bezel out. The green wire at the top right was barely on there and I didn't find where it went in the wiring diagram so I figured it was something the PO did.

timd02

Here are some pics that I took a few minutes ago and I was hooking up the factory connectors to the appropriate places. See any problems with the current set-up?

...Roger...

Tim, the ground for the center cluster is the center stud on the temp gauge , marked by the yellow arrow. (ignore the little potentiometer attached to the other stud) The black wire on the center stud must read ground using an ohm meter. The spade also needs to bolt directly to the metal housing with NO fiber washer.
The spark you talked about could also be that the shifter console is ungrounded and was using the center cluster for ground , both have their own ground.
(i tried to use one of your pics but I couldn't open it with paint to apply the yellow arrow)

timd02

Thanks for the info Roger. I will check to make sure I am getting a ground thru the black wire and also make sure that the ground tab doesn't have a fiber washer. How do I check the shifter console to make sure that it is grounded without removing it?

Alan 71

Hi Roger,
NICE!!!!
Regards,
Alan

timd02

I checked the ground spade on the temp gauge and it is sitting directly on the metal housing(no fiber washer). How do I check the connections with an ohm meter? Does the battery have to be hooked up to do this?

...Roger...

You can use an ohm meter between the console and a known good ground (usually the shifter is grounded). You can also check to see if the light in the shifter is lit up. You can also push the lighter in and see if it works.

...Roger...

No, just set to ohms and put one probe on a known ground and the other probe on what you want to see is grounded , the meter should read pretty close to 0 , if it flashes it usually means its not grounded.

...Roger...

Thanks Alan

SteveG75

That green wire is not stock. Looks like it is connected to from the fuel gage to pink wire of the temp gage (may just be the photo). Also looks like a bare end which could be shorting it.

timd02

The green wire is gone. It was just the photo making it look like it was hooked to the pink wire of the temp gauge. Not sure what it was running to unless it was used to hook up the radio by the PO.

Roadking

I would check the cigar lighter and be sure it is connected correctly and is not hot to the console. While the panel is out and not touching the console connect all gauges, turn the key and see what you have.

timd02

So I checked it with an ohm meter(old needle style) by touching the ground to the shifter and the red lead to the ashtray and it read 1.2 on the dial. The needle bounced all the way over near 0. Is it getting a good ground?

Sorry for my ignorance but electrical has never been my thing.

...Roger...

Touch your 2 ohm meter probes to each other and watch your meter,thats a good ground reading.
Not sure what you meant by 1.2 on the dial and then 0.

timd02

Sorry, The needle when the 2 probes touch moved towards the far right(O ohms) but stopped at 1. You will see what I mean on the pics below. All the probes I touched read that except for the battery gauge and it did not move(needle stayed all the way to the left).

7T1vette

There must be a power wire hooked to the wrong stud or you omitted an insulator bar on one of the gauges.

...Roger...

In the above pic you are reading resistance through the gauge not the ground.
Leaving the black probe on the center spade and putting the red on the metal case will confirm the spade is grounded to the case.

timd02

I get the same reading as the above pic. I also touched the ground probe to the shifter and the red probe to the shifter console and got the same reading.

timd02

Should I be getting the same reading on the battery tabs? I can touch the black probe to one tab and the red to the other tab and the needle on the gauge stays at the far left.