Random upshift light
12-06-2013, 10:36 AM
#1
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Year: 1988
Model: Cherokee
Engine: 4.0L In Line 6
Random upshift light
When I got it, it didn't work at all. Then it started randomly coming on for a few seconds at a time only in 1st and 2nd. Now it is even doing it in 5th.
What operates the upshift light and is their a fix.
What operates the upshift light and is their a fix.
12-06-2013, 12:01 PM
#2
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Year: 1989
Model: Cherokee
Engine: 4.7l stroker
Mine does the same thing it has to do with the RPMs and where it is connected to that circuit I am not sure. I just disconnect the light because i don't need my jeep telling me when to shift.
12-06-2013, 01:00 PM
#4
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Year: 1988
Model: Cherokee
Engine: 4.0L In Line 6
I don't either, just wondering if I could fix it.
I think it works off of manifold vacuum and TPS. High vacuum for throttle position starts a timer that lights the light for a few seconds. Makes sense considering I was going down a slight hill with enough throttle to hold speed. Doesn't make sense for 1st and 2nd though as I am under power accelerating.
I think it works off of manifold vacuum and TPS. High vacuum for throttle position starts a timer that lights the light for a few seconds. Makes sense considering I was going down a slight hill with enough throttle to hold speed. Doesn't make sense for 1st and 2nd though as I am under power accelerating.
12-06-2013, 05:28 PM
#5
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Remove the bulb.
12-06-2013, 05:56 PM
#6
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
That's kinda how I got my XJ, guy thought it was a service engine light. It still goes on and off all the time just because it can.
12-06-2013, 08:17 PM
#7
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Year: 1998 Sport
Model: Cherokee
Engine: 4.0
Just get rid of the bulb! If someone needs a little light to tell them when to shift it's time for them to buy a car with an auto trans.
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12-07-2013, 11:07 AM
#9
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Year: 1988
Model: Cherokee
Engine: 4.0L In Line 6
Sooo, **** OFF!
12-07-2013, 03:51 PM
#12
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Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
The PCM operates the light. The parameters at which it comes on are unknown and not documented anywhere except for some internal archive at Chrysler that details the PCM's programming. If you don't like it, you can either unplug the PCM or unplug the bulb.
Don't be a jackass.
Don't be a jackass.
12-07-2013, 03:57 PM
#13
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Year: 1996
Model: Cherokee
Engine: 4.0
If it makes you feel better, the light sucks when it works anyway and you'd probably just end up ignoring it.
12-07-2013, 04:17 PM
#14
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Year: 1999
Engine: 4.0
So... You need the light to function properly... Because u don't know how to drive a stick? I mean if u did, u wouldn't need to fix the light anyway.
Cruiser is an expert for a reason, and if he tell u to remove the bulb, you remove the damn bulb.
Cruiser is an expert for a reason, and if he tell u to remove the bulb, you remove the damn bulb.
12-09-2013, 03:05 PM
#15
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Year: 1997
Model: Cherokee
Engine: 4.0
im not sure if this helps but "On vehicles equipped with a manual transmission, ECU controls upshift indicator light. Indicator light is normally illuminated when ignition is turned on without engine running. Indicator light is turned off when engine is started.
Indicator light will be illuminated during engine operation in response to engine load and speed. If transmission is not shifted, ECU will turn light off after 3 to 5 seconds. A switch located on transmission prevents indicator light from being illuminated when transmission is shifted to highest gear." i also have a "yes or no" diagram that a shop would use to troubleshoot it but im not sure how to post it and make it still readable. This info was pulled up for an 88'.
Indicator light will be illuminated during engine operation in response to engine load and speed. If transmission is not shifted, ECU will turn light off after 3 to 5 seconds. A switch located on transmission prevents indicator light from being illuminated when transmission is shifted to highest gear." i also have a "yes or no" diagram that a shop would use to troubleshoot it but im not sure how to post it and make it still readable. This info was pulled up for an 88'.