early and late rev counter wiring changes

[rpgrainger]

Hi
i have a 75 dolomite 1850 and have a dash out of a pre 74 dolomite
i want to change all the gauges but the rev counters have different wiring
on the back of the late rev counter it has
spade connector(two green wires)
spade to casing(one black(earth))
male bullit connector(white with a grey stripe)
on the early rev counter
spade connector(two green wires)
spade to casing(one black(earth))
male bulit connector(plain white wire)
female bullit(white with a grey stripe)
as you can see the early and late cars had a white with grey stripe but on different bullit connectors....the extra white wire on the early dash goes into a bundle of wires that seem to go to the warning lamp and to the volt meter
just needto find out if the grey white do the same on both and where the extra white should go to
Cheers
Rob

[Silvery]

Sounds like the early one is in series in the lt circtuit - So it would be white in from the coil (dizzy side), then white/ grey (slate in the diagram key :) ) to the dizzy, IIRC. Meaning your ignition runs through it, creating another failure point...

[rpgrainger]

Would the feed from the coil also go to the warning lamp cluster and the volt meter
Cheers
Rob

[Silvery]

No, the feed from coil to dizzy (through counter) would be seperate to those - But it could be the feed goes switch>counter>coil I suppose, will have to see if I can dig out a diagram.

Edited - Diagram found :)

[Silvery]

Right, found a diagram...

White and yellow - From starter to coil, bypassing ballast resistor (live when starting)

Then, white and slate goes to the ballast resistor, white goes to the unfused ign switched (same as teh voltmeter warning light cluster).

So, the white side is easy enough to wire in, but the white/ slate needs to connect into the loom before the ballast resistor, otherwise you'll be running the coil at 12v. So if you can work out which white wire goes to teh coil and not the fusebox, warning lights etc then you should be fine. Otherwise you might have to start delving into the loom to find the resistor wire!

The front loom shouldn't have any whites in it other than the fusebox supply and voltmeter/ warning lights, so hopefully it won't be too tricky to work out the right one to connect up :)

[rpgrainger]

thanks
on the later cars how does the white slate run as i have the white/slate already at the rev counter.....
does the white slate do the same on early and late cars as one has a female connector and the other a male
Cheers
rob

[Silvery]

Later cars:

Green in from fused ign switched live

Earth to soldered on spade on counter case

White/ slate to dizzy side of coil

It sits parallel to the LT rather than in series, so it's not going to be a huge amount of help to you, as you still need to find the ballast resistor section for the input to the counter, which I imagine is the trickiest bit. You could then swap teh white/ slate over to the pos side of the coil so save on a bit of wiring though :)