Tacho Wiring

[Guest Brian T]

Hi guys. I gave up trying to get the indicators/hazards working on the stalk, I think as someone posted on another thread the switch assembly has given up the ghost, designed for tin top use only I guess, so, while awaiting delivery of my dash mounted indicator stalk, horn push and momentary switch and toggle switch for main beam plus warning lights ( a lot more associated with that little stalk than you first think !) Etc; I thought I'd make a proper start on my new dash and layout. I have bought some Carbon fibre effect plastic ,2mm, to go over the Exmo steel dash so hopefully should get Earth return through the dash.

 

The original Exmo dash was a very sad looking Sierra cluster stuck in the middle , I have got a range of Smiths clocks to take their place, and need a pointer in the right direction if poss? the Tacho is a Smiths RCV 2414 /00AF Neg Earth 4 Cyl , >7,000 RPM, ideal for the job. What I could do with is a wiring diagram or advice if possible. Had good look on the net and nothing much comes up regarding that Model? beginning to think it was "special application" for one particular model of car ,of which not many were made !

 

A word picture is the best I can provide at the moment as my wifes pinched the camera to go take photos of our new Grandkids, yep 2 in one week.

 

The back of the Tacho has an Earth spade connector direct to the body of the Tacho, so I guess that goes to a known good Earth, the Live feed for the instrument light that piggy backs to the side lights I'm assuming, and 2 other connectors, whether the colours of cables bear any resemblance to when straight out of the box heaven knows. One is a "Bullet" connector (male) which has a White/Black(stripe) single cable. The other ,very close proximity if that helps to identify, is a spade connector with 2 plain green cables.

 

None of the wiring diagrams I have found on the net show 3 wires (ignoring the light cable) in this configuration, the majority show a Live feed and then a single connection to the coil IIRC.

 

Any help or pointers to a wiring diagram much appreciated.

 

Thanks in anticipation.

[richardm6994]

Hi Brian,

 

I've never used smith gauges, mine are all ETB, however the only thing I can think of as to why you will have 2 green wires going to a single spade connector is that your taco may have come from a distributor-less set up, such as a zetec engine (more commonly known as EDIS).

 

The attached picture shows how the 2 signal cables are wired up to the taco.

 

 

If your not using the taco on an EDIS set up, then you'll only need 1 feed to the taco from your coil (which I would guess is you spade connector with green cables), as well as the +ve (your black and white bullet) and -ve supply (in addition to your bulb +ve supply).

 

You'll probably get better answers once we've seen photos.

 

hth

[Guest Brian T]

Hi Richard thanks for that, as far as I know it was fitted to a conventional Pinto ignition system, with coil and distributor, but ,the car had had a fuel injected and EDIS system at some point in it's history.

 

From what I can make out then the B/W wire would go to the + on the coil and the green (down to single cable) would go to the - of the coil ? Is that correct?

 

I will try and get some pics on a bit. Thanks again.

[richardm6994]

Hi Brian,

 

Not quite..........

 

B/W to 12v ignition

 

earth spade to good earth

 

green to -ve on coil

 

Bulb connector to 12v side light source

[Guest Brian T]

Ahhhh, right , thanks for that Richard. Very much appreciated ;-)

 

Just recovering from a near heart attack BTW. I've still been looking around for a Sierra Mk1 stalk switch just to make life easier, ( I have replacement hips,crawling under dashboards is not so easy ;-0 ), located a brand new switch ;-) Price? £117-80 + VAT !!!! Old stock since 1996, you'd think they'd be glad to get rid of it for £20 or so. Not a chance . lol. I got excited when the local breakers said they had one for £10, explained exactly what it was, went over there and it didn't have the horn push on the end ;-( never mind, wait for the bit's to come then do some wiring up.......

[richardm6994]

All the best with the heart recovery matey.......

 

I could be wrong here....but I didn't think sierra indicator stalks had the horn on the end......mine doesn't anyway (but it could be different mk numbers etc....).

 

ebay number 380410953062 illustrates an escort stalk.......very similar but has the horn on the end....is this what you are looking for? Obviously £75 is ridiculous but it might help with your search around breakers?

 

if all else fails......stick the cheap sierra stalk on without the horn and fit a push button on your dash for the horn (that's exactly what I've done)

[Guest Brian T]

OOOpps sorry Richard think I misled you, the near heart attack comment related to the stalk price not literally ,sorry.

 

Apparently the very early Sierra ones had the incorporated horn, similar to the ebay item you linked to. Mine is based on an 85 model. Retained the original number and logbook states Sierra based even got the DVLA letter confirming reg no retention.

 

The Mk1 Transit left stalk is the same but not sure if it will fit, steering column diameter etc? They do look very similar. I may see if I can get one of the other Mk 1 stalks and mount the horn on the dash (momentary push button) ,no horn option on the steering wheel.

[richardm6994]

Lol.......my bad!

[Guest Brian T]

I forgot to come back on this, sorry !

 

I fitted the tacho as you described, nice little hole through the bulkhead for the wire etc, put it all in place, checked the wiring, fired up, NOTHING

 

Checked against the wiring diagram , cleaned all contacts like brand new, retried, still nothing.

 

Oh dear..........

 

Well the tacho was dead then wasn't it? Wouldn't do any harm to rev her up a bit and play boy racer , much to the annoyance of neighbours (who perhaps shouldn't party hard the night before and keep me awake, OMG turning into a grumpy old man ! ) there I was merrily blipping the throttle imagining my nice shiny tachos needle bouncing up and down dancing along to the revs, hang on , this wasn't a very vivid imagination, my needle had jumped into life

Maybe it had a "sticky needle" as it had been stored for a while and perhaps just needed that extra little bit of a push to bring it back to life.

 

Thanks again for the info provided.

[richardm6994]

awsome dude......glad its working!

[Guest sadjagboy]

Brian,

 

I think you might have a tacho out of a triumph dolomite which needs some of the ignition power to the coil wired through it, looked far to complex for me to rewire my car to accommodate this odd set up, so I bought another 3 wire tacho on ebay. If the one you have has what looks like a male and a female bullet connectors aswell as a spade connector for power and another one for the earth, you have one of these odd ball tachos, I can try and take a picture of the back of it if you think you have one.

 

Best regards

 

Angus

[Guest Brian T]

Hi Angus thanks for the offer, I've managed to get it going thanks, you may be right that it was originally a Dolomite instrument, the original dash had one of those peculiar round combination instrument thingamebobs, 8 warning lights in a 2" dial ! Neat but just didn't look right so now changing my dash to lights and gauges here there and everywhere, always aspired to being a pilot, this is the nearest I can get to a cockpit ;-(

[Guest sadjagboy]

Glad you've got it working, very frustrating when things don't work as you expect.