Problems installing tacho

[Cannman07]

Well if you tell us the model it would help, but if you go off the old one colours and put them in order to your new one then it will work, u cant just use the harness even though it fits, using a small pression screw driver remove the pins and put them in the correct order.

It in a VX series 2 V6 manual. The wiring diagram for the SAAS 95MM Tacho is red wire to switched 12v, black wire to ground, green wire to rpm signal and white wire to battery for LED memory. The wiring for the small SAAS Tacho is the same but for some reason it has an extra orange wire to connect to battery for LED memory. I've got lights and power on the big tacho, the needle jumps up when the power is turned on but the rpm needle doesn't move after that. The green wire is definitely hooked up to a rpm signal because it's the same wire I use for the green wire on the small tacho so I'm confused as to why it won't get a rpm signal.

 

[Trevor loves holden.]

It in a VX series 2 V6 manual. The wiring diagram for the SAAS 95MM Tacho is red wire to switched 12v, black wire to ground, green wire to rpm signal and white wire to battery for LED memory. The wiring for the small SAAS Tacho is the same but for some reason it has an extra orange wire to connect to battery for LED memory. I've got lights and power on the big tacho, the needle jumps up when the power is turned on but the rpm needle doesn't move after that. The green wire is definitely hooked up to a rpm signal because it's the same wire I use for the green wire on the small tacho so I'm confused as to why it won't get a rpm signal.

But what harness plug are you using? The order which they plug into wont be the same if your using the old plug for your 52mm, also the SAAS model which IS it be good saying its 95mm which is 3.75" not the 3.5" which is 90mm ?

 

[Cannman07]

But what harness plug are you using? The order which they plug into wont be the same if your using the old plug for your 52mm, also the SAAS model which IS it be good saying its 95mm which is 3.75" not the 3.5" which is 90mm ?

Sorry for the confusion, both tachos have their own separate wiring harnesses. The plugs in the back of the tachos are completely different. The big one is 95mm and the little 52mm. But they wire up the same apart from the 52 mm having the extra orange wire as I explained above.

 

[ant797]

maybe you have confused the 12v battery orange wire car side for the ignition wire car side try connecting the wire you used for the 12v battery on smaller tacho to the ignition wire on bigger tacho

 

[Trevor loves holden.]

Sorry for the confusion, both tachos have their own separate wiring harnesses. The plugs in the back of the tachos are completely different. The big one is 95mm and the little 52mm. But they wire up the same apart from the 52 mm having the extra orange wire as I explained above.

Well I think I worked it out for you, the white wire goes to +12v constant power not the illumination like the old one.

 

[Cannman07]

Thanks for your help too

Well I think I worked it out for you, the white wire goes to +12v constant power not the illumination like the old one.

Thanks, I'll have a go wiring up the big one tomorrow and see how I go.

 

[Trevor loves holden.]

Thanks for your help too

Thanks, I'll have a go wiring up the big one tomorrow and see how I go.

Your welcome his the link, Note the white wire to battery + = constant power. If you turn your lights on then it will work with your set up as long as its not on dim.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&cad=rja&uact=8&ved=2ahUKEwjYieeso4znAhVPyjgGHbdZAIMQFjAPegQIARAB&url=https://www.shopsaas.com/assets/files/install/MuscleTachLargeFitting.pdf&usg=AOvVaw00jb8JPrCFwnYu_p1zRm3h

 

[Cannman07]

Your welcome his the link, Note the white wire to battery + = constant power. If you turn your lights on then it will work with your set up as long as its not on dim.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&cad=rja&uact=8&ved=2ahUKEwjYieeso4znAhVPyjgGHbdZAIMQFjAPegQIARAB&url=https://www.shopsaas.com/assets/files/install/MuscleTachLargeFitting.pdf&usg=AOvVaw00jb8JPrCFwnYu_p1zRm3h

Had a go hooking it up today, followed your instructions with the white wire and still no luck. I have power to the unit, lights and the function button works to set the revs for the shift light but no rev signal. I've got the green wire (rpm) connected to the rpm signal wire at the back of the instrument cluster, I know it's the signal wire because it works with the other tacho using the green wire for rpm. I'm stumped.

 

[Trevor loves holden.]

Had a go hooking it up today, followed your instructions with the white wire and still no luck. I have power to the unit, lights and the function button works to set the revs for the shift light but no rev signal. I've got the green wire (rpm) connected to the rpm signal wire at the back of the instrument cluster, I know it's the signal wire because it works with the other tacho using the green wire for rpm. I'm stumped.

This maybe the issue as they use 5v on commodore, its in the installation guide,
Problem: “ECU tach output is only 5volts”
- If the tach output from your vehicles ECU is only 5volts, a 10K 1/4 watt resistor is needed to increase the signal voltage to 12volts. (Nissan, Subaru, Etc..)
Installing a resistor: Connect one side of the resistor to the green signal wire of the tacho and connect the other side of the resistor to the red 12volt ignition wire of the tacho. Do not cut any wires, just splice into.
WARNING: Do not connect the resistor to any other wire or you WILL damage the tacho and your ECU!
-

 

[Cannman07]

This maybe the issue as they use 5v on commodore, its in the installation guide,
Problem: “ECU tach output is only 5volts”
- If the tach output from your vehicles ECU is only 5volts, a 10K 1/4 watt resistor is needed to increase the signal voltage to 12volts. (Nissan, Subaru, Etc..)
Installing a resistor: Connect one side of the resistor to the green signal wire of the tacho and connect the other side of the resistor to the red 12volt ignition wire of the tacho. Do not cut any wires, just splice into.
WARNING: Do not connect the resistor to any other wire or you WILL damage the tacho and your ECU!
-