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Black Button Under Dash

12K views 59 replies 29 participants last post by  gemsheba 
#1 ·
Alright, so I bought a used 2002 TB LT about two months ago. The first time I detailed it, and when I do this, I'm thorough. I found a wire tucked up by the steering column under the dashboard with a button on it. I fiddled with it and finally got it to do something. When the truck is running, If I hit the button, it turns off the odometer completely, and you can hear a click like a solenoid being activated. Now I saw one post about "odometer killers" but have never heard of such before. The truck has 92k miles on it, according to the odometer, but should I be worried. Does anyone have any general knowledge specific to TB and these sort of buttons? IS it legal?
Prior history of the vehicle.
It started out as fleet, it was fleet for two years, then it was privately owned for 11 months, then it was a company car, then I bought it.
So is it possible that the Fleet had it installed to keep the value of the car up?
The car is in excellent shape, and runs like a champ.
Thanks for reading, and thanks for any possible clues/help.

-Mark
 
#3 ·
I thought that, but when the car is running, the lights are on the dash and the rpm shows idle. when you hit this button, everything cuts off on the dash, no lights...The only way I can explain what it does, is that it bypasses everything on the dash..

here is a pic

 
#5 ·
As far as being illegal, I believe a switch to disconnect the odometer would violate state and federal laws.:m2: You say the dash goes dark? Can you still drive? Could this be like the lockout used on emergency vehicals? It looks to professional manufactured to be something illegal.
 
#6 ·
I would follow it, but I honestly don't feel comfortable taking the dash apart just yet. I reckon I could hit the button and drive around alittle bit and see if the mileage changes at all. If it does not change, that would be a head on the nail as to what it does, right?

Should I go to the dealership and notify them of it, not like they can do anything about it, maybe the dmv?
 
#7 ·
The DMV would be the best place. If you sell the vehical and it is found that the odometer has been tampered with you could be held liable. You could try doing a serch on something like Carfax and see if the mileage seems correct. Good luck
 
#8 ·
The mileage ads up on the car and carfax report. I made the dealer print me out a copy before I bought it, but I never really thought about that little switch till I read about odometer kill switches on here. The only reason I would suspect it, was because it was a fleet vehicle.
 
#9 ·
It would be a remote switch for just the lights on the dash, is there an overlay on the guages something aftermarket?

I used to have one of those switches to control 12v power so i'd follow it... dont be afraid to take the dash apart follow the how tos on here i'll go step by step!

Let us know what u finds tho we'd all be interested!!
 
#12 ·
Still sounds like someone just figured out a way to black out the dash. I don't think that cutting that circuit is going to stop the odometer from functioning. Companies that buy fleet vehicles don't really give a crap about mileage, all that is negotiated in when the vehicle is purchased. I know we have black out switches on all of our work vehicles. That switch looks like the one that came with my neons from streetglow. check and see if it also kills the headlights or any other exterior lights.:cool:
 
#13 ·
So no big deal then?
Whew.:duh:
I thought the switch looked familiar, I've seen ones like it. I just could not understand why there would be a switch to turn off the lights on the dash.
So is that fuse that's split in half safe, or should I just remove the whole thing?
 
#16 ·
All our vehicles are purchased from the GM fleet plans. I work for a law enforcement agency. We do a lot of surveillance. The Impalas we have actually have a switch on the dash, installed at the factory, that says "surveillance mode". Our non GM vehicles have a switch that was installed aftermarket. :cool:
 
#17 ·
I remember an article on another board several years ago that mentioned that pulling a certain fuse, would make "Time stand still". What the prior owner did was hardware an electronic switch/relay into that fuse. Everything else on the dash works, except 'time stands still' from what I've read and have been told when the fuse is absent. Yes GM actually wires just the odometer function to its own fuse, I don't understand the reasoning, but they do. - Go figure.

Highly illegal and odds are that the vehicle has more mileage on it than you thought, when you bought it. Please don't post the fuse number, although it's possible to figure it out in the picture. (I'd pull the picture too, just be one the safe side, you don't want to be liable for somebody duplicating the wiring to manipulate the mileage). Now the question arises do you do something about it with whom it was purchased from, as the ONLY reason that circuit is present is to limit the mileage shown on the odometer.
 
#18 ·
yea, that is EXACTLY what it does....
It just got dark out, so I went to see what I could get to happen. I messed with the switch again, the driving lights came on, and to my surprise the cluster was backlit, but not as bright as normal. The park drive etc box was turned off, and so was the mileage/time etc box.

I reckon I can go to the dealer and show them... but I don't wanna part with my car, but I do feel a bit taken advantage of. Sorry the thread no longer makes sense because I pulled those pictures down. I never even noticed the wires to the fuse box when I bought it. Thing was hidden very well
 
#19 ·
That fuse is for the IPC, but looking at the schematics the IPC also gets power from the ignition voltage so I would assume the odometer would still work that fuse pulled. Have you driven it with the switch pressed to see if the mileage changes or not anyway?
 
#21 ·
There could be some other reason they wanted the dash dark. As ghoster said, it could have been used for surveillance or something. I know I've seen in a "newer" Oldmobile, it had a button on the dash (that is factory) that would turn off the gauge cluster and all the lights on the dash. I'd definately be curious to know whether it actually disables the odometer, though it shouldn't in my opinion. Do let us know though.
 
#22 ·
Yea I will check it out. It cannot be for the all the dash lights, because it just makes them dimmer. They appear off in the day, but they are still on at night time. There is no other button I have found that turns them off at night, nor have I found a light cutoff switch for the headlight/breaklights, so the whole night stalking thing is out of the question. My tb has running lights so they are always on. All the switch does is cut the two little boxes off in the cluster now. To me, it seems pointless if they went to that work and it does nothing. I will test it out tomorrow and see what happens. Thanks everyone for the help and support. I really like it here, lots of great resources and you never feel ashamed to ask a question. :thx
 
#23 ·
Its not night stalking, its surveillance. And thats exactly the way I would expect it to work. At night, you can just turn off the lights, but the gears and the mileage continue to glow ( if the vehicle is running). So they need an independant kill switch. Obviously if the vehicle is moving people know someone is there, so its pointless to have a kill for every other light. I would bet that that is what its for.:cool:
 
#24 ·
but you cant turn the lights off if the vehicle is running, unless you have that on a switch as well, which I have not found one. Although there was a cellphone antenna that I removed, and never could figure out where the other end was...
Sorry, I'm not fussing or stating what you are saying is incorrect, I don't know that side of the field like you, so you have a professional opinion, but I just don't see how it could be for that if there is no apparent kill switch for exterior lighting as well.
 
#25 · (Edited)
I could turn mine off with it running. As long as it was in park, you twisted the light switch counter clock wise and then released it, as I recall. It was a momentary switch, didn't stay in that position. It would turn off all the lights though. I think some of the older ones didn't have that switch position. Yours may not have it. :cool:

Why not just go drive it? Jump in, leave it on, go 5 miles. Turn it off and drive home. Lets see what it does. Now we are all just curious!!
 
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