Upshift Light

GSequoia · Mar 16, 2006

Hey All,

The upshift light on my '88 Chief isn't working. The lamp is good and it will come on in a key on/engine off situation but it will not illuminate while driving (and I've wound it up in first up to approximately 4,000 rpm, damn lack of a tach!).

The Transmission fuse (7.5A) is good as I just replaced it due to non functional backup lamps.

Thanks!

Also just to re cover the pertantant infromation:
1988 Cherokee
4.0 / BA10 / 231

Wayne Sihler · Mar 16, 2006

Vac line missing,plugged,broken ?
Wayne

GSequoia · Mar 16, 2006

It uses vacuum? I haven't checked into all the vacuum stuff yet (just got it on Sunday) but intend to when I go through the vehicle. I do know that the HVAC works as intended and the axle doesn't so the ball might be ruptured (although most likley it's those crap connections they used for the axle and transfer case switch).

Would you happen to know where it's routed?

outlander · Mar 16, 2006

Why do you need it anyway?It's just an idiot light......This is my second xj and that little light lied about shift points on both of them.I wouldn't count on that light to do anything for mileage or performance.

GSequoia · Mar 16, 2006

Don't intend to count on it... I just like to make things work right for some strange reason.

RichP · Mar 16, 2006

Yea, its vac triggered, it's a manifold pressure idiot light, don't know if it's direct or electric, on the 97+'s it's electric but still vacum only turned on by the dash controller.

tvisXJ · Mar 16, 2006

I've never seen any that have worked properly. Mine sometimes comes on while in nuetral lol.

Wayne Sihler · Mar 16, 2006

GSequoia said:
It uses vacuum? I haven't checked into all the vacuum stuff yet (just got it on Sunday) but intend to when I go through the vehicle. I do know that the HVAC works as intended and the axle doesn't so the ball might be ruptured (although most likley it's those crap connections they used for the axle and transfer case switch).

Would you happen to know where it's routed?

I hope this is it,It is located on the pass side inner fender,back by the blower motor.It has a vac line and a wire into it.Has a blue cap on it.
Any way thats what I think it is ,but it may be something in the 4wd system as my 4x4 light is on all the time.My 87 has the Vac lines for the 4wd running off the back of the TC.Its a 231AMC case.
Wayne

87manche · Mar 16, 2006

I've found that mine is a bit strange in my 87. Seems that it only comes on in light throttle acceleration. Anything past about 1/4 throttle will not trigger the light. Mine also comes on in 5th at light throttle. That thing works by voodoo, sacrifice a chicken to it.

Kejtar · Mar 16, 2006

GSequoia said:
Don't intend to count on it... I just like to make things work right for some strange reason.

LOL

stewie · Mar 16, 2006

87manche said:
That thing works by voodoo, sacrifice a chicken to it.

x2. that might work. but is it pleasing to the Jeep Gods?

8Mud · Mar 16, 2006

Wayne Sihler said:
I hope this is it,It is located on the pass side inner fender,back by the blower motor.It has a vac line and a wire into it.Has a blue cap on it.
Any way thats what I think it is ,but it may be something in the 4wd system as my 4x4 light is on all the time.My 87 has the Vac lines for the 4wd running off the back of the TC.Its a 231AMC case.
Wayne

I'm pretty sure that's the charcoal canister purge solenoid.

My upshift light works well (I have a AW4, got to love Jeeps), when the alternator is failing. I'm guessing they share a ground.
I pretty sure the upshift is operated by the ECU and has an interruptor switch for high gear on the five speed.
There is some kind of circuit, that lights the trouble lights at start up, that on later models (early 90's) goes through the ignition switch. Not sure about the early Renix (but likely also). Two different circuits, one to test and another to activate.
My best guess is ECU, through the 5 th gear deactivation/interruptor switch, to the light, then to ground. I'm not exactly sure how/if the igntion switch is wired to test the lamps.
The brake trouble light and the upshift share a ground connector as does the Engine toruble light farther down the line a bit.

Eagle · Mar 16, 2006

jeepdeepfreak said:
Why do you need it anyway?It's just an idiot light......This is my second xj and that little light lied about shift points on both of them.I wouldn't count on that light to do anything for mileage or performance.

x2

Forget making it "work right." It doesn't work right when it works. The one in my '88 would have had me in 5th gear going up a steep hill at 25 MPH. Say a prayer to the Jeep gods that you don't have that idiotic piece of excrement flashing at you all the time. I pull the bulbs out of every one I get.

87manche · Mar 16, 2006

8Mud said:
I'm pretty sure that's the charcoal canister purge solenoid.

My upshift light works well (I have a AW4, got to love Jeeps), when the alternator is failing. I'm guessing they share a ground.
I pretty sure the upshift is operated by the ECU and has an interruptor switch for high gear on the five speed.
There is some kind of circuit, that lights the trouble lights at start up, that on later models (early 90's) goes through the ignition switch. Not sure about the early Renix (but likely also). Two different circuits, one to test and another to activate.
My best guess is ECU, through the 5 th gear deactivation/interruptor switch, to the light, then to ground. I'm not exactly sure how/if the igntion switch is wired to test the lamps.
The brake trouble light and the upshift share a ground connector as does the Engine toruble light farther down the line a bit.

With the key in the on position and the motor not running mine will light up. that's normal per the Renix FSM
I'm also pretty sure that the ECU is involved in making it light up.
I don't think it has a 5th gear switch, Mine comes on in 5th all the time when I begin to coast down a hill. I think the ECU lights it whenever the engine conditions are met, regardless of gear. Either that or my 5th gear switch is broken, but other than the backup light switch I don't think there are any other connectors on my trans.
Voodoo.

ajeeperwannabe · Mar 16, 2006

stewie said:
x2. that might work. but is it pleasing to the Jeep Gods?

if the chicken wont work im sure sacrificing a yota would

87manche · Mar 16, 2006

ajeeperwannabe said:
if the chicken wont work im sure sacrificing a yota would

I wonder if the gods are angry that I put yota rock sliders on the MJ. Only good use for yota parts is putting them on a jeep I suppose.

Wayne Sihler · Mar 16, 2006

8Mud said:
I'm pretty sure that's the charcoal canister purge solenoid.

No ,this hose ,wires don,t go to the canister,Hooks into the vac system at the lines for the shift fork for the front axle.
Wayne

Jeff in VA · Mar 17, 2006

So Geoff, lemme get this straight.....

you wanna keep the "Chief" decals, AND you want the upshift light to work too?

What kinda voodoo trance this thing got you in? Pass the dutchie, dude...:speepin:

I got a set of OEM mudflaps, if ya want 'em...

Jeff

GSequoia · Mar 17, 2006

Jeff in VA said:
I got a set of OEM mudflaps, if ya want 'em...

Nah, I don't live in Utah.

It's a stocker, it's gonna stay a stocker mostly (no lift or any silliness like that but I will update some creature comforts). If something's a stocker I'm gonna make it right!

outlander · Mar 17, 2006

Wayne Sihler said:
8Mud said:

I'm pretty sure that's the charcoal canister purge solenoid.

No ,this hose ,wires don,t go to the canister,Hooks into the vac system at the lines for the shift fork for the front axle.
Wayne

Click to expand...

that blue thing is the vac switch that lights up the 4x4 indicator light.......

and concerning the up shift light on my 89 5 speed it is somehow wired to the back up light circuit(don't ask me why) because while trying to complete my ax15 swap I accidentally wired 2 of the four wires up down there in an attempt to get my b/u lights to work and that made the up shift lamp come on untill I unhooked the wires.

Upshift Light

Everyone says I'm a jerk.

NAXJA Member

Everyone says I'm a jerk.

NAXJA Forum User

Everyone says I'm a jerk.

NAXJA Forum User

NAXJA Forum User

NAXJA Member

NAXJA Forum User

PostMaster General

NAXJA Forum User

NAXJA Forum User

Lifetime NAXJA Member

NAXJA Forum User

NAXJA Member #1367

NAXJA Forum User

NAXJA Member

<---respect

Everyone says I'm a jerk.

NAXJA Forum User

Similar threads