Tachometer Hook-up

jclarkey · Post by **jclarkey** » Mon May 06, 2013 1:17 pm

Trying to figure out how to hook up my tachometer as it was not hooked up when I got the car. Buddy said "you could just hook it back up" so it makes me think that it is a pretty simple fix.

From everything I can see in my wiring diagrams, it looks like I am just missing having the brown tach wire hooked up to the coil. There is a loose unattached wire right by the coil so I assume that is the right one. All the wires are hooked up behind the dash, and other than one loose black and white wire at the fuse box, everything else seems to be hooked up. Do I simply attached the brown wire to the coil and I am good to go? Which terminal, positive or negative? Doesn't appear to be any additional hook ups so I guess it will just piggyback on the correct terminal.

Bonus points if you can help me identify the black and white wire. I don't seem to have instrument panel lighting. Is this all I need for that as well?

seabeelt · Post by **seabeelt** » Mon May 06, 2013 1:21 pm

What year car. Hard to tell from just the description

jclarkey · Post by **jclarkey** » Mon May 06, 2013 1:57 pm

seabeelt wrote:What year car. Hard to tell from just the description

Sorry, 1974 Spider.

jclarkey · Post by **jclarkey** » Mon May 06, 2013 2:45 pm

As far as the black and white wire goes, it appears there is two empty spots on the fuse box. From what I can tell 5 and 6.

jclarkey · Post by **jclarkey** » Wed May 08, 2013 6:55 am

I went ahead and tried to hook up the brown wire to the negative side of the coil. The car would then not start. I decided to take it off and she started right up. Either that was a coincidence or was part of the problem. Debating on whether or not I should try the positive side but am worried that I will damage some wiring in the process.

Any one have any suggestions?

fiat218 · Post by **fiat218** » Sat Jun 01, 2013 12:47 pm

jclarkey wrote:I went ahead and tried to hook up the brown wire to the negative side of the coil. The car would then not start. I decided to take it off and she started right up. Either that was a coincidence or was part of the problem. Debating on whether or not I should try the positive side but am worried that I will damage some wiring in the process.

Any one have any suggestions?

Tac wire goes to the positive side. But some one will verify that before u attempt

I'm no mechanic,just a masonry man

westy64 · Post by **westy64** » Sat Jun 01, 2013 3:57 pm

fiat218 wrote:
jclarkey wrote:I went ahead and tried to hook up the brown wire to the negative side of the coil. The car would then not start. I decided to take it off and she started right up. Either that was a coincidence or was part of the problem. Debating on whether or not I should try the positive side but am worried that I will damage some wiring in the process.

Any one have any suggestions?
Tac wire goes to the positive side. But some one will verify that before u attempt
I'm no mechanic,just a masonry man

TACH DO NOT GO TO POSITIVE ON COIL !!!

Tach signal comes from the negative blade of the coil.
Wire should be brown, but you need to check with an ohmmeter if this brown wire at the coil does go to your tach.
Good luck.

fiat218 · Post by **fiat218** » Sat Jun 01, 2013 6:02 pm

westy64 wrote:
fiat218 wrote:
jclarkey wrote:I went ahead and tried to hook up the brown wire to the negative side of the coil. The car would then not start. I decided to take it off and she started right up. Either that was a coincidence or was part of the problem. Debating on whether or not I should try the positive side but am worried that I will damage some wiring in the process.

Any one have any suggestions?
Tac wire goes to the positive side. But some one will verify that before u attempt
I'm no mechanic,just a masonry man
TACH DO NOT GO TO POSITIVE ON COIL !!!

Tach signal comes from the negative blade of the coil.
Wire should be brown, but you need to check with an ohmmeter if this brown wire at the coil does go to your tach.
Good luck.

Whew, good thing u said

jclarkey · Post by **jclarkey** » Tue Jun 04, 2013 7:21 am

TACH DO NOT GO TO POSITIVE ON COIL !!!

Tach signal comes from the negative blade of the coil.
Wire should be brown, but you need to check with an ohmmeter if this brown wire at the coil does go to your tach.
Good luck.

So I hooked it up again to the negative and once again the car would not start. This was after a nice drive as well. Took the wire off and she started right up. Any ideas on what the heck is going on?

fiat218 · Post by **fiat218** » Tue Jun 04, 2013 7:27 am

Maybe that not the tac wire, just saying

westy64 · Post by **westy64** » Tue Jun 04, 2013 4:38 pm

fiat218 wrote:Maybe that not the tac wire, just saying

you're probably right.

westy64 · Post by **westy64** » Tue Jun 04, 2013 4:46 pm

jclarkey wrote:

TACH DO NOT GO TO POSITIVE ON COIL !!!

Tach signal comes from the negative blade of the coil.
Wire should be brown, but you need to check with an ohmmeter if this brown wire at the coil does go to your tach.
Good luck.
So I hooked it up again to the negative and once again the car would not start. This was after a nice drive as well. Took the wire off and she started right up. Any ideas on what the heck is going on?

did you check if this brown wire goes to the tachometer in the dash ?

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