68notray

Trying to get my gauges tested & working on a 69. I think I may be missing a ground.

Clock works great out of the car. In car hooked up does not. I do have 12 V constant at the orange wire.

All the gray wire instrument light bulbs test good but none come on when snapped into place.

Seat belt warning bulb tests good but won't illuminate. BUT the jumper wire supposed to supply it's voltage does not register 12 V anyway.

Fuel gauge does work fine and temp gauge moves a fraction when key is turned on so it may be working not sure yet.

I will add there is a double black pair of wires behind there not connected yet, don't know what it connects to yet. But not a ground these are hot

Alan 71

Hi 68,
There are several dedicated grounds for the dash harness including one that's screwed to the inner side of the left side hinge pillar.
In addition the bezel for the center gauges is a ground.
Regards,
Alan


This is the location for 71... might your 69 have a similar ground connection? Notice a ground at the tach and speedometer also.

68notray

Obviously both speedo and tach are mechanical, so I guess that ground is for the instrument lights? Think that is also the ground for the other gauges? But - on mine the speedo/tach instrument light do work, the ones for fuel temp etc do not.

caskiguy

Notice the Black ground(s) on pillar as Alans diagram points out.
Notice the ground locations on the Gauges

derekderek

the 2 black wires you feel are hot may be the grounds. they seem hot cuz the circuit is not completed until they are attached to ground. be careful though. if they ARE hot, you don't want to screw them down and turn on the key. but I don't think they used black wire as a hot anywhere.

bazza77

yes , instrument back lights (grey wire i:e 20GY) ground wire is black i:e 14B

here's the 69 aim wiring , you can see it along the right hand side ,



here's some other pages that show parts of it ,




no idea why it went upside down , but if you look right at the radio ,it has a ground location written



hope this helps you

0Willcox Corvette

The small gauge cluster picks up ground through the temperature gauge middle terminal which would also mean that if the fuel gauge is working fine, then the ground is complete. So I think you have a different issue.

You can verify this ground by removing the connector from the temperature gauge and with the key on, test the positive wire with the ground on the connector. The lower wire on the connector is the positive wire. If this ground is good then your issue is somewhere else.

What is odd is that you say the fuel gauge is working and if it's working then there is a ground present on the housing. And if it's working the clock should work (if it works on the bench).

Willcox




Below is a wire schematic, if you click on it and then click on the enlarge icon. You can then right click, select copy and open your paint program up.. then paste it into paint and save to your desk top. Once you do this you can trace the circuits if needed.

Willcox
http://repairs.willcoxcorvette.com/w...ire-added2.jpg

7T1vette

The fuel gauge is grounded back at the tank. The ground is part of the gauge sender circuit; it's run to the right frame rail.

0Willcox Corvette

Charlie, I agree...

But for the fuel gauge in the dash to work the housing must have a ground... If the temp gauge is not grounded then the fuel gauge will not work.

So based on this, if his fuel gauge is working it's picking up ground on the stud marked 5 in the picture below and this can only happen if the housing and temperature gauge is grounded... unless Bubba has been a factor...

68notray

Wow thanks for all the help. Another thing is the seat belt warning light seems to get power from a small black jumper wire that goes to the adjacent gauge. My MM is showing no power to that connector .... I did find that the double black is indeed a ground and have connected it to the bare stud on the heat/ac mechanism, although that doesn't help my gauges as the two aren't touching

0Willcox Corvette

The seat belt warning gets its power from the lower stud on the fuel gauge. If you don't have power on the pink wire this would explain why your fuel gauge isn't working.



The middle bolt in the picture below is the grounding for the module.

68notray

I am the dumbest guy alive.

YEP - I DIDN'T CHECK THE FUSE

We'll that explains why the gauge lights don't work, the 5 A inst lgts fuse was blown. That got all my lights and warnings working. Some terminal cleaning and better connections got all gauges working too. Only the clock isn't working. Still works fine on the bench though.

caskiguy

It happens.