Gauge wiring question

[tvrmk363]

Hi Guys,

I finished putting my dash back in place after a trimming job. Thanks Mark for straightening out the picture (in the "what's happening in your garage this weekend") for me. When I use my iPhone all kinds of strange things happen.

Anyway got it back in and it looks pretty good, I think. I had an issue with the fuel and oil pressure gauges. They are both reading full scale. Do any of you electrically inclined guys know off the top of your heads what might be causing it? Wires plugged in backwards?
I hate wiring and sort of go into mental block status when confronted with an issue. HELP!

[phillpot]

They both work on the same principle, a live (when ignition on) to one side of the gauge and a wire from other side to earth, either via the sender unit in the fuel tank or the oil pressure sender on the engine.

Sounds like "some one" has put the live to them but an earth direct to the other terminal?


ETA there will be an earth on each gauge but that should be to the casing, it is only there to make the lamp work




Ignore the green arrows!

Ignition live to where it says 10v dc.

Wire from "resistors here" terminal goes to sender unit.

earth the central mounting stud and the lamp holder in the big hole

Edited by phillpot on Monday 8th May 15:54

[tvrmk363]

I'm guessing the picture is of a Smiths guage? My VDO's are different. My ground wires attache to a lug on the case of the gauge. I'm thinking I may have crossed the green wires (one has a blue tracer) when I hooked the fuel gauge back up.
I took pictures when I was taking things apart and it's not to clear as you can see.

I thought I had pictures of every step but the oil press gauge seems to be missing. I guess I can just swap the leads and see what happens.

[phillpot]

tvrmk363 said:

I'm guessing the picture is of a Smiths guage? My VDO's are different.

Yes could well be, just a generic picture courtesy of Google... hopefully juggling a few wires will sort you out