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ground for gauges

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F

fordhealey

Jedi Hopeful
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replaced my speedo cable. now my gauges only work intermitantly.i know the cable supplies the ground for
some of them. at what point do i need to establish a new ground to eliminate the problem?
gregg
 
I think the center post nut for the U bracket gage mountings originally had a ground wire for each gage. The U bracket does not make reliable contact with the back of the panel. Among other things, this can make the fuel gage read low.
D
 
Are you saying the other gauges are not working? I'm not sure what the speedo cable has to do with the electrical unless you caused a problem while working in the confined spaces back there. If its the speedo not working there may be a problem with the cable is too long.
 
the speedo cable is supposed to be part of the grounding system if you look at a 61 3000 wireing diagram. without the cable installed, the electrical gauges don't work properly. after installing a new cable my gauges work
intermittantly. the new cable is apparently not grounding.
it is not a healey cable or housing.this was explained to me once before. thought it was on this forum. maybe it was
on the modified site (i run a 289). when i removed the broken cable originally, a lot of the gauges quit working.
they started working after i installed the new cable, but
i still seem to have i weak ground.sometimes things work
sometimes not.
gregg
 
[ QUOTE ]
the speedo cable is supposed to be part of the grounding system if you look at a 61 3000 wireing diagram. without the cable installed, the electrical gauges don't work properly.
gregg

[/ QUOTE ]
I have looked at the wiring diagrams & also wiring harnesses. There are black ground wires to the gages.

Stop & think about it. Not even Lucas woud chose such a silly & unreliable design as to use the speedo cable for an electrical ground. The gage itself is meant to have a rubber ring between the bezel & the front of the dash panel. As I said before, the U mounting bracket on the back often makes poor contact with the metal on the back of the dash since the back was originally painted. The gage grounds are chained together & grounded at a point on the firewall near where the voltage control was supposed to be.

Maybe in the conversion/modification process some wiring was left out.
D
 
I am not an A-H guy (as much as I would love to be... Beautiful cars and who could mistake the sound?) but I am a "Friend of Lucas" and it wouldn't surprise me if the grounds were a "Daisy Chain" so if you didn't have a ground through your clamp you could hope one of the other gauges did or perhaps even through the speedo cable.(although I have to agree even Lucas wouldn't <u>plan</u> on a ground through the speedo cable)So run a ground wire to a real ground point from that daisy chain and you should be back in business. /ubbthreads/images/graemlins/cool.gif
BTW The Jag crowd has dubbed this a "Redundant Ground" as if that gave it some kind of class!! /ubbthreads/images/graemlins/wink.gif In actuality if it were truly redundant, why are you installing it?
Lucas is famous for insufficient grounding... so when all else fails.... ground it again /ubbthreads/images/graemlins/grin.gif

Mike
 
OH MY Gosh No /ubbthreads/images/graemlins/nonono.gif! the speedo cable is not used as a ground at any time unless you forget to hook up the engine to chassis ground. Included in the wire harness should be a ground wire that fits under the knurled attaching screw post on the back of the meters.If it is missing add them as required.---Keoke
 
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