# MkII ABA Swap: Tach Not Working?



## QUIRKiT (Dec 19, 2006)

Ok, I've got a '91 Jetta with an ABA OBDII out of a 96 Jetta. The car runs great and everything works well, except for the tach.

I'm using the original MkII cluster and the tach just won't read. I think it was never hooked up...

I'm assuming the fix is just to splice off of the harness somewhere? Anyone know an easy fix?


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## Salsa GTI (Aug 29, 2000)

tie your tach wire ti the neg side of the aba coil its under the little flippy cap
that is all


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## QUIRKiT (Dec 19, 2006)

Salsa GTI said:


> tie your tach wire ti the neg side of the aba coil its under the little flippy cap
> that is all


Your explanation is so detailed and precise!  

But seriously, I understood it, so thank you for the help! :beer:


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## Salsa GTI (Aug 29, 2000)

LOL...i was waiting for the WHERE IS THIS FLIPPY CAP responce

But you knew what i was talking about


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## i4turbo (Oct 26, 2006)

seriously, were on the back of the cluster do I need to send the neg of the coil too??? i cant seem to find it 

89 jetta ce2 aba swap


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## Svedka (Jul 4, 2008)

T/28 from your gauge cluster/tachometer it is a solid green wire 

T28/10 Tachometer U1/06 Green Green Green 

Reference 

http://www.a2resource.com/electrical/CE2cluster.html 

or you can hook - from the coil to 

G1/12 Ignition Coil Pin 1 (all Mk2, most others '90 only), ECU tach signal (all 91+ except Mk2) Tachometer Red/Black (coil) or Green/Black (ECU) 

http://www.a2resource.com/electrical/CE2.html


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## bayareafast (Apr 7, 2008)

i could be retarted but how does one go about connecting into the negative side of coil. i see the two leads under the lid there and i assume the one on the side where the ground is, is the negative post? theres no marking and no legit way to connect something onto there. would i tap into a wire coming off of coil or some how wrap a wire around the metal strip? thanks a ton!


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## Butcher (Jan 31, 2001)

Take all the wires off one of the posts and move them so they cannot touch the body of the car. Turn on the ignition, use a test light to see which wires have power [the ones attached to the coil or the ones that you just removed]. You could also check the wiring diagram and find it out that way too. Most German cars use a green wire on the triggered side and black on the power side.

Every coil I have ever touched always are labeled. Most are cast into the top of the coil. Circuit 15 is usually the power side, 1 is the trigger side [grounded side].


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## bayareafast (Apr 7, 2008)

tried both sides of coil and got nothing on the tach? is my tach wack? on the tach it has two wires for hot and two for ground. i have both grounds together and hot together, would this be an issue?


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## vweatsvtec (Dec 16, 2009)

Take the green wire straight from the back of the cluster and cut it before it goes into fuse box. Then run that wire through the firewall and to the coil. Put a female spade connector on it and put it on the neg side of coil. I’ll look when I get home which side it is. And the cluster will work. 


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## bayareafast (Apr 7, 2008)

Thank you brother, but no sweat I got it figured finally.... One of the 12v leads didn't have sufficient contact. Ugh lol


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## vweatsvtec (Dec 16, 2009)

Ahh well hope it wasn’t to hard to figure out 


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