Dash light won't go off

sweetN8ivegrl

New Member
Joined
Dec 3, 2023
Messages
3
Location
Pioneer, CA
Ok. I've had my '90 YJ for around 10 years. I've been through it all and, yes, I've Just  Emptied  Every   Pocket..
Anyhow I decided to take the time to go through the cowl area (?) having done most all the rest.
My dash lights have never had the cover to tell me what is what since I bought it. I looked on Google and the light that stays on, only when the key is off the light is on. No light while engine is running...I'm asking why. Is it because my vacuums lines at currently disconnected?
Help a girl out please I need ideas
 
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very few 90 cars are on the road, when I see one , I am shocked. very rare on the road.
are you on the road pavement? ore on a farm pulling stumps like my buddy.? tires in the dirt/mud?
what does can area mean? (under hood? or a the vacuum servo motor CAN? it looks can'ish. sure.

did you pull vacuum lines>? yes those at the servo motor must not be pulled off. or front axle goes dead or sticks in 4wd locked front axle. in 4wd up front.
I presume the 4wd lamp is off key off, not sure about your statement.


first make sure the kids (any in the hood or etc) did not put the car in to 4wd and get it locked in to 4wd, on pavement, it is part time 4wd for dirt or show.
not for the hard pavement !. if you drive the car and the steering fights your hands the transfer case is stuck in 4wd. the fix is easy. on all part time 4wd.
so move the car to loose dirt on the curb go real slow and shift to 2wd, see if the lamp goes out. curb or grass or dirt or gravel,sand find a loose surface.
force the shift lever into 2wd, make rear sure it did that. ( go slow, dead slow and it makes it more easy not stopped dead)

this ends 4wd 101, part time basics.

it is not any Awd CAR. (googling 4wd gets you a zillon wrong answers for AWD)
YES IT CAN FAIL IN MANY WAYS:
EACH WAY IS S TEST TO FIND THE POINT OF FAILURE.
WHERE YOU START Testing is your call. ( i jack it up first see if the 2 front axles are locked, to each other) if are the dash lamp did not lie to you.
what I do is what I said above, make sure its in 2wd for sure.

I unplug the 4wd switch on top right of front axle of lamp goes out key on, the switch is closed, if stays on the cluster wiring is wrong.
if goes out we know 2 things now.
the switch is bad or the slave vacuum motor is stuck in 4wd, so out comes the hand vacuum pump(+gauge) and I pump it to unlocked,
if i jack up the front end now, and both front tires are locked, and left or right spins the other, the axle is locked in 4wd,
that means the vacuum motor is bad (as I already did the vacuum test) and it is bad or far far worse. (the axle has damage on the right side front
now lets say the vacuum test shows the front is now free and the lamp goes out.
then the vaccum hose or the switch called the 4wd vacuum valve is bad. at the front top of the transfer case.
each step is test, some tests take tools ,do you have tool or want to buy them.
or just wild guessing.
ok the hose fell off.
redux1. just words, and too many questions but it is not simple?,. well is compared to AWD.
in fact it it all works perfect even if the lamp is burned out and the switch that runs it is dead wrong bad.
The lamp is tell tale only.
handy but not a show stopper in the snow.
if the front tires are dead in in the snow that is a real problem.(or ice/mud/dirt)
 
very few 90 cars are on the road, when I see one , I am shocked. very rare on the road.
are you on the road pavement? ore on a farm pulling stumps like my buddy.? tires in the dirt/mud?
what does can area mean? (under hood? or a the vacuum servo motor CAN? it looks can'ish. sure.

did you pull vacuum lines>? yes those at the servo motor must not be pulled off. or front axle goes dead or sticks in 4wd locked front axle. in 4wd up front.
I presume the 4wd lamp is off key off, not sure about your statement.


first make sure the kids (any in the hood or etc) did not put the car in to 4wd and get it locked in to 4wd, on pavement, it is part time 4wd for dirt or show.
not for the hard pavement !. if you drive the car and the steering fights your hands the transfer case is stuck in 4wd. the fix is easy. on all part time 4wd.
so move the car to loose dirt on the curb go real slow and shift to 2wd, see if the lamp goes out. curb or grass or dirt or gravel,sand find a loose surface.
force the shift lever into 2wd, make rear sure it did that. ( go slow, dead slow and it makes it more easy not stopped dead)

this ends 4wd 101, part time basics.

it is not any Awd CAR. (googling 4wd gets you a zillon wrong answers for AWD)
YES IT CAN FAIL IN MANY WAYS:
EACH WAY IS S TEST TO FIND THE POINT OF FAILURE.
WHERE YOU START Testing is your call. ( i jack it up first see if the 2 front axles are locked, to each other) if are the dash lamp did not lie to you.
what I do is what I said above, make sure its in 2wd for sure.

I unplug the 4wd switch on top right of front axle of lamp goes out key on, the switch is closed, if stays on the cluster wiring is wrong.
if goes out we know 2 things now.
the switch is bad or the slave vacuum motor is stuck in 4wd, so out comes the hand vacuum pump(+gauge) and I pump it to unlocked,
if i jack up the front end now, and both front tires are locked, and left or right spins the other, the axle is locked in 4wd,
that means the vacuum motor is bad (as I already did the vacuum test) and it is bad or far far worse. (the axle has damage on the right side front
now lets say the vacuum test shows the front is now free and the lamp goes out.
then the vaccum hose or the switch called the 4wd vacuum valve is bad. at the front top of the transfer case.
each step is test, some tests take tools ,do you have tool or want to buy them.
or just wild guessing.
ok the hose fell off.
redux1. just words, and too many questions but it is not simple?,. well is compared to AWD.
in fact it it all works perfect even if the lamp is burned out and the switch that runs it is dead wrong bad.
The lamp is tell tale only.
handy but not a show stopper in the snow.
if the front tires are dead in in the snow that is a real problem.(or ice/mud/dirt)
Thank you. Now I know where to start. I think I know thanks to all the replies. To answer the one question, she's my everyday driver. Work, store,to my parents or just to the nearest mud hole. I've got some hours of grease monkeying to do. I'm wanting to check out the "American Trail".. dirt road coast to coast..man what an adventure that must be. Thank you for your help
 
very few 90 cars are on the road, when I see one , I am shocked. very rare on the road.
are you on the road pavement? ore on a farm pulling stumps like my buddy.? tires in the dirt/mud?
what does can area mean? (under hood? or a the vacuum servo motor CAN? it looks can'ish. sure.

did you pull vacuum lines>? yes those at the servo motor must not be pulled off. or front axle goes dead or sticks in 4wd locked front axle. in 4wd up front.
I presume the 4wd lamp is off key off, not sure about your statement.


first make sure the kids (any in the hood or etc) did not put the car in to 4wd and get it locked in to 4wd, on pavement, it is part time 4wd for dirt or show.
not for the hard pavement !. if you drive the car and the steering fights your hands the transfer case is stuck in 4wd. the fix is easy. on all part time 4wd.
so move the car to loose dirt on the curb go real slow and shift to 2wd, see if the lamp goes out. curb or grass or dirt or gravel,sand find a loose surface.
force the shift lever into 2wd, make rear sure it did that. ( go slow, dead slow and it makes it more easy not stopped dead)

this ends 4wd 101, part time basics.

it is not any Awd CAR. (googling 4wd gets you a zillon wrong answers for AWD)
YES IT CAN FAIL IN MANY WAYS:
EACH WAY IS S TEST TO FIND THE POINT OF FAILURE.
WHERE YOU START Testing is your call. ( i jack it up first see if the 2 front axles are locked, to each other) if are the dash lamp did not lie to you.
what I do is what I said above, make sure its in 2wd for sure.

I unplug the 4wd switch on top right of front axle of lamp goes out key on, the switch is closed, if stays on the cluster wiring is wrong.
if goes out we know 2 things now.
the switch is bad or the slave vacuum motor is stuck in 4wd, so out comes the hand vacuum pump(+gauge) and I pump it to unlocked,
if i jack up the front end now, and both front tires are locked, and left or right spins the other, the axle is locked in 4wd,
that means the vacuum motor is bad (as I already did the vacuum test) and it is bad or far far worse. (the axle has damage on the right side front
now lets say the vacuum test shows the front is now free and the lamp goes out.
then the vaccum hose or the switch called the 4wd vacuum valve is bad. at the front top of the transfer case.
each step is test, some tests take tools ,do you have tool or want to buy them.
or just wild guessing.
ok the hose fell off.
redux1. just words, and too many questions but it is not simple?,. well is compared to AWD.
in fact it it all works perfect even if the lamp is burned out and the switch that runs it is dead wrong bad.
The lamp is tell tale only.
handy but not a show stopper in the snow.
if the front tires are dead in in the snow that is a real problem.(or ice/mud/dirt)
The transfer case is in 2 wheel drive
My vacuums lines are not connected as I'm replacing them. My biggest quarry is this, ONLY when the engine is OFF does the light come on and stay on. Also to answer your question, i drive my jeep everywhere. Like my dog where i go the jeep goes. I live in the Sierra Nevada foothills in California. I drove out to Coos bay and took every backroad east till i got to Kansas... twice. Idaho, Nevada.... she's my go to girl.
 
Thank you. Now I know where to start. I think I know thanks to all the replies. To answer the one question, she's my everyday driver. Work, store,to my parents or just to the nearest mud hole. I've got some hours of grease monkeying to do. I'm wanting to check out the "American Trail".. dirt road coast to coast..man what an adventure that must be. Thank you for your help
The American Trail, sorry to admit this is the first that I’ve heard of it. I’ll have to check this out.
 
I Revised my oldest post on topic here.



I put a video there of men vacuum testing the whole front axle vacuum motor.
to prove what is failing. is 15 min work with a hand vacuum tool.
just did it mine, fast



older_CommandTrac.jpg

the china funky servo motor will not fit at all, (see nipple making V shape those are junk, the real servo nipples are in parallel .(oem was)<<<FYI

more,,,, HARDWARE
how it really works is here, mech. actual.
d30 , dana
shift to 2H and drive and do so driving 1/2mph,dead slow. the vacuum valve then moves part ID 26 the locker slider dog ring to 2wd disconnected.
if not the lamp(4WD) sure does stick on. key on. or running. ( also can be wired wrong or shorted wires to whatever) or vacuum hoses backwards.
that is how it works. there are no springs here, so it stays where you last put it , key off or stalled.
The SW switch tells you what the VAC last did key on or last running, and mine has no self test keyon. at all.
The housing 31 has 5 oz of GL5 lube oil and if dry it jams. the housing 31 is not part of the main axle.(lube)<< lots of things can go wrong. as you can see.
or do my right front tire off the ground test see HERE.


this test is 15 minutes work. 5 or less tire off ground.(jacked)
If you spin the tire, now, and the pinion does not spin that means it is in 2H (really) and the switch SW is bad 4w lamp glows wrongly.,


dogs.JPG
ID 26 is the axle locking dog ring. spline'd
 
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The American Trail, sorry to admit this is the first that I’ve heard of it. I’ll have to check this out.
Well I found the American Discovery Trail or ADT, it runs right past me but it is a non motorized trail. I think that I found the one your talking about Trans American Trail. It also comes almost to my door, I’ll be checking this out.
 
My biggest quarry is this, ONLY when the engine is OFF does the light come on and stay on (but not key off sure)
that hints of wired wrong.?
the switch does not move unless engine is started, only vacuum will do that. (via transfer case valve actions)
the switch does not move when you key off. or stall the engine,
There are no springs in the servo motor at all.(oem stock)
or alien wrong servo motor installed that has springs dead to rights wrong.?<< called jerry rigged.(ww2 slang)
also if hoses are pulled it is possible for sure that the servo motor is stuck half way ! and lies to you. (the switch too, may be intermittent 30 years old)
so shift to 2wd driving dead slow for sure 1 tire up front or both on dirt or ice and not pavement so it can completely UN- dog the part ID 26 and not have
the switch get confused. (1/2 in and out)
I pay no attention to my lamp , because I know if the front is locked or NOT by how my hands feel, if locked in 4wd the steering fights my hands.
for sure on pavement. I need no lamp at all , (and mine is burned out).
part time 4wd is super simple and lets you know fast of front axle is locked, ( sure me singing to the Choir )
I can test the front axle , jacked up. for locked or not. and.
I can use my hand vacuum pump and lock it or unlock it at will. (a the servo motor nipples hoses pulled) at will. easy as pie.
I can cheat it and put yellow to RED hose jump and now in 4wd say stuck in snow.
if the vacuum motor diaphragm is cracked (leak down test fails,same tool ,SOP) it can cause it to fail at random times or is dead.
the same tool allows me to see if the transfer case valve is failing. using the vac gauge of the tool ,easy,
They lamp is not really needed by me, I know when the front end locks. and if the front prop shaftt works.
now what if the servo deep inside the diaphram is 30 year old and stiff as heck. and now acts like spring , it has mind of its own now, SHOT to H3LL
That is all I can dig up. ( keep in mind old cars can have a double failure here not just 1. ) mine had like 100 things wrong.(expected too)
 
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