i have a harlan. when i turn the car on, the light comes on as usual. however, it doesn't ever come on when at the rpm it's supposed to. i've hit the limiter 2-3 times trying to make it work. it just won't do it. i assume the ground/power wire are fine, correct? so it should be the rpm wire that's causing the issue? i respliced the wire and checked it's connection on the shift light, but it still won't work. thoughts?

 

You've checked your positive.. ground... and retapped the PCM tach wire.

Sounds to me like your Harlan has just taken a dump. Check into getting a Raptor if you can't get your Harlan replaced..

 

well, i figured the ground and the power wire are both not worth checking since the light comes on at start. if either of those were the problem, the light would not turn on at startup. so it has to be the tach wire. does that make since, or is my logic skewed?

 

You right.. Check your tach connection..

 

i did check that. i re-spliced the wire that goes to the tach, and i re-connected that same wire to the shift light. but the light still doesn't come on. i have a power tester (one of the things from wal-mart where you plug the ground into, and touch the part where it has power, and then a light lights up). but i'm afraid to use that on the tach wire.

is there anyway i can find out if the tach wire is sending any information to the shift light or not? if it is, then the tach wire is not at fault, and it's probably the shift light. if there is no signal, my wire is bad. i just did this about 2 weeks ago, so that would blow my mind if either of those are the case. damn luck.

 

You know that the pcm is sending info because your factory tach is still working (or is it). I think your shiftlight has taken a dump..

 

The ground and power wires have to be good, otherwise the light would not come on at all. So yes, that's a check

The only wire left is the tach one. Make sure the connection is good, and there are no cuts along the wire. However, are you 100% positive you are using the right wire?

Last, make sure that you have the shift light setup for a 4 cylinder. If it's setup for an 8 cylinder, it will not work properly. LS1's tach output is a 4 cylinder instead of an 8

 

really??? i went along with what installuniversity said, and i'm pretty sure they told me to do it by 8 cylinders. the BIG thing is that this light worked flawlessly for about a month until it recently crapped on me.

any other thoughts?

 

Switch the settings for the light to work in 4 cylinder mode.. Well, for my Raptor to work I have to run it in 4 cylinder mode.

You should give it a try.

 

the 4 cylinder mode is how it's set up on install university, so that's how i set mine up. i'm going to try it again anyway, and see if i can get it to work. i'm also going to set the light at a lower rpm setting so that i don't have to take my car to 5600 rpms everytime i want to check that damn light!

 

Also, make sure you have the right 12v wire. I accidently hooked mine up to a pink wire with a black stripe, instead of the plain pink wire. My shiftlight would come on when I started the car, but it didn't come on when it hit the desired RPM. Since yours was working before, I don't know if thats the problem.

Kevin

 

If your factory tach in the car is like mine it is 200-300rpm off from what the computer reads it as.

Just thought I would put that out there..

 

this should be screaming failed unit man. i highly doubt your wire went bad on you a month later. especially if you re-tapped the wire and it still doesn't work. hit harlan up and see what he can do for you.