Hi everyone! My issue is that my up shift light is not coming on. Is this a sensor that's out? Possibly transmission speed sensor? 2000 jeep wrangler 4.0 4x4 nv3550 manual transmission. Any help is great thank you!
Up shift light not working
- Thread starter stayrad 86
- Start date
You don't want it. The dummy light is ridiculously inaccurate, and if I used the dummy light in the 3 manual vehicles I've ever owned, I'd get nowhere. I have a 1.4 liter Jetta that wants me to shift into second at like 1300 RPM.
I'd imagine the bulb is out or a PO removed the bulb because they got tired of looking at it. Many people here on the forum have done the same. I know you said yours is a 4.0, but the SE's didn't have a dummy light (you gotta really rip a 4 banger TJ to get it over it's own weight, dummy light would be even more useless)
I think it's not a bulb issue. Surprisingly after I took it to the beach and washed it. The up shift light started working. But I guess after it dried it stopped working. Lol anyways it's a good tool to teach my wife. Also it helps me identify parts. Which in turn helps me when I'm troubleshooting. Do you know if it's a sensor or where I can start?
It sounds like you might have a moisture issue with the wiring or connections related to the up shift light. Given that it started working again after washing your Jeep, it could be a corroded connector or a loose wire that’s temporarily making contact when wet.
I’d suggest starting with the wiring harness that connects to the up shift light. Check for any corrosion or damage to the connectors. If everything looks good there, you might want to look at the transmission speed sensor as it can affect various functions, including the up shift light. You can check the wiring and condition of the sensor itself.
How can you safely drive and know when to upshift without it? You're "living on the edge". 
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Disabling that light was one of the first 2 things I did when I got HP Tuners. It bugged me for 20 years.
There is no sensor in the transmission telling it what gear you are in. The only electrical connector there is the reverse light switch. The shift light is signalled by the PCM from some combination of load, engine rpm and speed that jeep determined would enable them to squeek by the CAFE light truck fleet standard of 20.7mpg at the time (1997). It's not a straight shift at N rpm light.
If your speed sensor on the transfer case output is having connectivity issues your speedo should be bouncing or showing erratic speed changes. Throttle position is one of the inputs and it causes other issues on failure. RPM comes off the crank position sensor on top of the bell housing and you'd have alot of issues if it were bad, like a check engine christmas tree. If neither of those;
That's an incandescent bulb that's been going on and off the most of any light in your dash and the bulb could be failing, which would be the better option. The worse option is an issue in the wiring harness between the PCM and cluster.
There is no sensor in the transmission telling it what gear you are in. The only electrical connector there is the reverse light switch. The shift light is signalled by the PCM from some combination of load, engine rpm and speed that jeep determined would enable them to squeek by the CAFE light truck fleet standard of 20.7mpg at the time (1997). It's not a straight shift at N rpm light.
If your speed sensor on the transfer case output is having connectivity issues your speedo should be bouncing or showing erratic speed changes. Throttle position is one of the inputs and it causes other issues on failure. RPM comes off the crank position sensor on top of the bell housing and you'd have alot of issues if it were bad, like a check engine christmas tree. If neither of those;
That's an incandescent bulb that's been going on and off the most of any light in your dash and the bulb could be failing, which would be the better option. The worse option is an issue in the wiring harness between the PCM and cluster.
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Teach her properly, with ears listening to the engine revs and eyes checking the tach for reference. No need for an idiot light.
Teach her properly, with ears listening to the engine revs and eyes checking the tach for reference. No need for an idiot light.
Yep. This reminds me of the person who wanted to put the shift pattern somewhere on the dash because his daughter kept looking at the gear shift handle. No : teach her to know the shift pattern without looking at anything.
Teach her properly, with ears listening to the engine revs and eyes checking the tach for reference. No need for an idiot light.
What?!? You can teach a wife something?
KennethS
TJ Addict
Yeah, but you can't see it because it's hidden by the steering wheel.There’s a shift light?
How can you safely drive and know when to upshift without it? You're "living on the edge".
Easiest way to remember is wait until you are between 4500-5500 rpm. That is the sweet spot.
That idiot light will only teach her to short shift and lug the engine. Unless you can have it reprogrammed to be an actual shift light, I suggest you ignore it.
Teach her properly, with ears listening to the engine revs and eyes checking the tach for reference. No need for an idiot light.
What about when we're tickling the limit with our mower, then do we need a shift light?
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