Harlan Shift Light Help
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TECH Junkie
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From: Sandusky, Ohio
Harlan Shift Light Help This is an epic fail for me 
ALL of the wiring i've done over the years...and I can't get a 3 wire shift light to work for me lol
sodered all the connections, 12v keyed, ground and white #10 from the pcm...programmed it (yes in 4 cylinder mode) and set the rpms
everything flashed back correctly but when i got to the rpms to test it, nada, nothing, zip
Can i take my 12V test light to the tach wire to see if it's getting power AT the shifter, or will i fry it?
i haven't a clue why it isn't working, the wire isn't busted or anything. Ran an 18g wire from the PCM to the light, heavier than what was supplied, but still light in my opinion.
Things to try?
Connect to something else? if so, what? and how to program - i.e. change modes on the light?
ALL of the wiring i've done over the years...and I can't get a 3 wire shift light to work for me lol
sodered all the connections, 12v keyed, ground and white #10 from the pcm...programmed it (yes in 4 cylinder mode) and set the rpms
everything flashed back correctly but when i got to the rpms to test it, nada, nothing, zip
Can i take my 12V test light to the tach wire to see if it's getting power AT the shifter, or will i fry it?
i haven't a clue why it isn't working, the wire isn't busted or anything. Ran an 18g wire from the PCM to the light, heavier than what was supplied, but still light in my opinion.
Things to try?
Connect to something else? if so, what? and how to program - i.e. change modes on the light?
Thread Starter
TECH Junkie
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From: Sandusky, Ohio
I can, but I am 100% positive it is the correct wire.
It's on the "red" PCM which is on the bottom of the two. pulled the plastic cover off, found pin #10, which was a white wire, per the directions, spliced into that
Only thing I can think to try, that wouldn't chance frying the light would be to test the voltage at the splice and then at the light....
It's on the "red" PCM which is on the bottom of the two. pulled the plastic cover off, found pin #10, which was a white wire, per the directions, spliced into that
Only thing I can think to try, that wouldn't chance frying the light would be to test the voltage at the splice and then at the light....
IIRC, the wire I tapped was white (but it has been a LONG time ago), so it sounds like you got the right wire. Provided the tap is actually making contact with the copper wire and not just the insulation (I've had it happen to me before), I wouldn't know what else to check. As long as it is set to 4-cyl, and you are obviously getting good power and ground since you are able to program it, that is the only thing missing in this equation.
What kind of tap are you using?
What kind of tap are you using?
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Verdad Gallardo Well, put a multi-meter to the soldered connection at the PCM and ground the meter to wherever and see if you get a voltage output with the engine off, and then with it running.
pretty sure you want it in 8clyn mode...
installuniversity.com has a good write up on how to do it
sounds like your wiring is correct since it flashes back, but i think you have it on the wrong mode...
installuniversity.com has a good write up on how to do it
sounds like your wiring is correct since it flashes back, but i think you have it on the wrong mode...
NO, it goes in 4cyl mode. You know the light has power since it flashed back to you. Really sounds like there is something wrong with the tach signal from the pcm. Thats where my bet is
Thread Starter
TECH Junkie
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From: Sandusky, Ohio
Our engines send 2 pulses per rev, so it's set to 4 cyl. mode...or something similar like that.
I believe it'll work on 4 and 8 cyl. mode, just is more 'accurate' in 4 cyl. I'm sure the difference isn't anything that we could ever notice
Harlan's an electrical guy, you know how those guys are
Still a stand up guy, he drove to my house to check out my light, can't be more happy!
I believe it'll work on 4 and 8 cyl. mode, just is more 'accurate' in 4 cyl. I'm sure the difference isn't anything that we could ever notice
Harlan's an electrical guy, you know how those guys are
Still a stand up guy, he drove to my house to check out my light, can't be more happy!
Thread Starter
TECH Junkie
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From: Sandusky, Ohio
unit was fine, when I did the final shrink wrap over all 3 wires, i slightly melted the inside shrink wrap, to where just 1 strand of wire was sticking out of the ground and tach, so the tach signal was grounding out
I just ordered mine and already printed out the install directions off of installuniversity. My question is this; If I want to mount the shift light on the driver's side A-pillar in the defrost vent, can I follow those directions, or is there another write-up somewhere more specific to installing the shift light there?
I just ordered mine and already printed out the install directions off of installuniversity. My question is this; If I want to mount the shift light on the driver's side A-pillar in the defrost vent, can I follow those directions, or is there another write-up somewhere more specific to installing the shift light there?