Dedicated gauge grounds

[shum8]

Ok - I am in the process of running a dedicated ground bus throughout the chassis. Have mounted a ground block under the tailgate for the rear grounds, and will be adding blocks under the dash and on the firewall. My question is specifically for the Temp and Fuel gauge grounds. They usually ground thru the speedo case, but I would like to ground them to the ground block as well. Should I just leave em grounded to the speedo case or would it be better to ground them to the ground block? If so, where should I tie into the gauges? everything else is pretty straightforward, but these two have me scratching my head.

Thanks

Rob

 

[j6824]

When I redid mine not too long ago I ran a bus bar, too...ran a ring terminal off one of the speedo mounting studs to the bus bar...just to be sure

 

[Torxhead]

The CJ should already have a ground wire from the negative battery post to the firewall. You could extend this to the dashboard to improve the ground connection on all the circuts that use the dash.

 

[shum8]

I agree - but I wonder if I should individually ground the fuel and temp gauges?


Sent from my iPad using Tapatalk

 

[Torxhead]

The fuel and temp gauges are grounded at the dash where it is screwed on. Providing there is a good ground at the firewall, adding additional wiring will not hurt. This could be checked with a multimeter. Adding those serrated lockwashers will help here. Other weak points on the CJ would be the frame ground on the gas gauge send unit, the ignition control module, and the windshield wiper motor. The highest amp draw would be the starter motor and adding a ground wire to the alternator housing won't hurt. Anywhere the CJ uses the poorly conductive steel for an electrical connection could use some help.

 

[shum8]

The fuel and temp gauges are grounded at the dash where it is screwed on.

Ok -I hate to beat a dead horse here, but sometimes I'm not the sharpest tool in the shed, and until I get my head wrapped around something I tend to be a little dense. I've always heard the Temp and Fuel gauges get their ground from the speedo housing, which is grounded to the dash via their mounting studs. I just can't for the life of me see how...... Then again, I don't have an electrical background, so...... Probly why I can't see it.

Problem I'm having is this: looking at the pic below, the Temp and Fuel mounting studs are surrounded by an insulator (B), and there are two tabs folded over (A), which I assume are holding the gauge together.



When the Temp gauge is mounted, the tabs may or may not touch the speedo housing (C) - can't be the ground path. The two studs are insulated from the housing (D), as are the nut on the mounting studs (E).





Funny thing is, the speedo head IS grounded to the housing (F,G), but I don't thing it was a requirement - speedo and odometer is mechanical.





Would someone please explain to me how the Temp and Fuel gauges are grounded to the speedo housing mounted like this without an additional ground circuit? Like I said - sometimes I can be as dense as a pine knot, and I think this is one of those times.......

Providing there is a good ground at the firewall, adding additional wiring will not hurt.

Will be grounding both the tub and dash to the new ground circuit.

Other weak points on the CJ would be the frame ground on the gas gauge send unit, the ignition control module, and the windshield wiper motor. The highest amp draw would be the starter motor and adding a ground wire to the alternator housing won't hurt. Anywhere the CJ uses the poorly conductive steel for an electrical connection could use some help.

All of these will be getting a dedicated ground.....


[/QUOTE]

 

[yellow85cj]

Don't think the Fuel and temp gauges are grounded to the speedo.

Their grounds are the frame from the tank sender (or you could run a direct ground if you have the wire and the time), and the engine block. Now there is a pesky little ground sign in the drawing but it is not anything directly for the gauge. The speedo housing does need to be grounded for the lights to work properly. The speedo is grounded when you bolt it to the dash which is grounded to the tub when you bolt it on, which is grounded by the tub, which is grounded by the grounding straps to the frame and tub. Whew!

Since I had a bare dash, I welded 3 X 1/4" bolts to the back and am running a 6ga (most likely over kill) wire from a bus bar from the battery neg terminal. Then everthing has a ground to these (speedo, oil pressure & voltage gauge, heater lights etc) and actually the tail and lights and fuel sender.

So, you don't have to keep wondering how they ground with the "insulating" paper. That is what the paper is for, to isolate them. If you do ground them individually, they probably will not work and have to be replaced.

For the temp and fuel see diagram below.

 

[shum8]

Ah HAH - I get it now..... and it makes perfect sense.. I forgot about the temp sender and fuel sending unit grounds...... Man, looking at the gauge and trying to figure out where the ground path was kicked my buttocks LOL.

I will also be welding a couple studs to the backside of the dash for a ground point that ties into the ground bus. By the time I get this thing done (if I live long enough) it'll have grounds if nothing else.

Thanks for the explanation...... I feel smarter now


Sent from my iPad using Tapatalk

 

[shum8]

Well that is going to be a most interesting read.... after dinner. However, I am missing the ground clip on the back of the fuel gauge......



Guess I need to test the fuel gauge and open the temp gauge and inspect..... there was an aftermarket temp gauge in the dash - bet I now know why....


Sent from my iPad using Tapatalk

 

[Lumpy Grits]

I would suggest you run a dedicated GND wire from the dash's panel to the battery NEG(-)post.
Coat the connectors with battery terminal spray to maintain full conductivity.
Currect engine temp and fuel tank readings depend on a good dash GND.
LG

 

[shum8]

In post #9 above, there is a small spring metal tab crimped under the heavier metal tabs - I'm assuming it is there to maintain ground to the speedo housing. Mine is missing the tab:



So I added a ground wire - soldered it to one of the tabs, and ran the wire out the back of the housing. Will solder a ring lug on the end and stick it under one of the speedo cluster mounting stud nuts, then onto the dash ground circuit......








Think that'll work?


Sent from my iPad using Tapatalk

 

[Lumpy Grits]

:ty: Your pictures are outstanding.
Know'n how to solder is a lost art these dayz.
I learned while building radios.
LG

 

[shum8]

Thanky, Sir -

I don't have a problem with soldering - it's finding the lead solder than can be challenging..... I now have a stash that would probly get me thru 3 or 4 rebuilds


Sent from my iPhone using Tapatalk

 

[Lumpy Grits]

Yup, finding true 60/40 rosin core is all but impossible in PRK.
Have my inlaws ship it to me

 

[shum8]

Ok - Played with some wire and stuff this afternoon.... here's what I've started with.



I will be attaching another ground line from the other screw on the back of the housing to the ground bus. That will give me sumthin to do tomorrow...


Sent from my iPad using Tapatalk

 

[Lumpy Grits]

You could just mount the GND on the speedo to one of the speedo mounting studs.
For GND connections, I recommend the use of external star washers as they 'bite' into the surface. When done-Coat all GND connections with battery terminal spray.
LG