• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Tachometer wiring

Share this page

G

Guest

Guest
Guest
Offline
Hey all,

Need some help again :p I just received a new tachometer for my now negative ground car. I am not sure how to wire it though.

On my original (pos ground) tacho there were 3 wires. On this one there are 3 wires as well. One of them is for power, and I will be able to find that one easily by measuring the voltage on the three old connections. I do not know however which of the two connections left I'll have to connect where on my tacho (still with me? /ubbthreads/images/graemlins/smile.gif).

So basically. I have 1 power. And the two for the actual measuring of which I do not know which one to put left and which one right.

Does this actually matter? Can I just try it without damaging anything? Or should I be careful with which one to connect where .. ?
 
Hi Dreas - I'm just curious ... what reference books and other sources do you check when you have questions about your MG?
Tom
 
Hi,

Too many stupid questions from my side? Could be /ubbthreads/images/graemlins/smile.gif

First I check my M. G. B. Owner's Workshop Manual, which is usually not specific enough (not for these kind of things at least), next I check my Haynes MGB Restoration Manual which has not provided a solution so far /ubbthreads/images/graemlins/wink.gif Then I check at google and this forum for any information. And if I cannot find it I simply post it.

Any better suggestions?
 
Dreas - your post doesn't say who made your new tach, but wasn't there a connection diagram in the box? Also, it would help to know the colors of the wires (both on your tach, and the three from the harness) before I plunge deeper into this. Anyway, do you have a 1964 MGB wiring harness diagram? I found a couple on the 'net if you need one.

Say - I only asked about sources to see what you had. Sorry if I sounded otherwise.

Veel geluk! (bonne chance?)

Tom
 
Hehe np,

Ok let's see. The old tacho (a rebuild one) had three wires. Red, blue and green. I assume the green one is for power, but I still have to verify that. The red one was soldered together with two other wires. Same for the blue one. On my tacho however I do not seem to have any identification of which connector belongs to which wire. The only different is there is a male bullet connection and a female bullet connection.

The wiring diagram for my 1964 MGB is in the Haynes manual but the problem is not all coding corresponds properly to the wires in my car especially not with the tachometer. I've tried to figure out which wire leads where but that's quite hard to tell.

I'll probably just give it a try today and suppose I cannot damage my tacho by reversing the pulse wires.
 
OK - to get started, what are the colors of the three *harness* wires your old tachometer used? Not the tachometer's wires, but the color of the three wires it was soldered into (the three which hang from inside the dash).
 
also - what company did you get your replacement tach from? and their part number? I'll also email you a good ref I use on MGB electricals. You just need to decide which free harness wire goes to the un-shielded male connector on the back of the tach.
 
Back
Top