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Dash Lights Problem


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RyanV
User

Aug 15, 2010, 7:02 PM

Post #1 of 12 (3385 views)
Dash Lights Problem Sign In

Hello,
I got such great help with my stereo in the stereo forum, so I thought I would post about my dash lights here. I have a 1997 Geo Metro 4 cyl. hatchback. The kid who owned it before me put in a stereo, and he did not know what he was doing, and apparently he caused some electrical problems. When I bought it, the tail lights and the dash (instrument panel) lights were not working. The turn signal indicators worked (and still do) and check engine light and so on, but not the lights that light up the spedometer. I checked the fuses right after I bought it, and there were a few blown out. So I changed those out, and the dash lights came on, as well as the tail lights, and that helped me get home, but then they would go out if I hit a bump in the road, and by the time I got home they were out for good. Changing the fuses after that has not helped, and the fuses seem to be fine.

Anyway, I rewired the stereo, and now the tail lights work, but the dash lights still do not work. The radio works great now. I checked the fuses, and they seem to be fine. I bought a circuit checker thingy with a light that lights up in the handle (in order to check the wires in the radio, which were fine), and I checked the wire connector going to the dimmer adjuster dial switch thingy to adjust the brightness of the dash lights, and I got no light coming on. Perhaps I did it wrong. I clamped one side of the circuit checker to a hunk of metal and used the needle-tip awl thingy to touch inside the connector in all three ports, but no light came on. So anyway, does anyone know what could be the problem?

Thanks,
Ryan


Sidom
Veteran / Moderator
Sidom profile image

Aug 15, 2010, 10:17 PM

Post #2 of 12 (3374 views)
Re: Dash Lights Problem Sign In

Yea there is a couple of pretty sharp guys over in that section, Jk306 is one of them. Problem being Tom pretty much keeps em locked up over there with his darn "attack cat" so we'll have to try to muddle thru here on our own.....

We really need to look at a wiring diagram, I'll try to see if I can't find one.

Most dimmers are basically an adjustable resistor of some sort that lower the power source to dim the lights depending on how many wires goes into yours will determine if it has it's own power source but one wire should have power on it. The feed from the rest of the lights.

On thing you can check is to see if the dimmer works on any other lights inside other than the dash. Usually it will control the lights in the switches and other stuff. If it's controlling other lights then you are going to have to focus on the leg that feeds the instrument cluster.

From what you've posted it really sounds like you have a short somewhere, it was working, you hit a bump and it went from an intermittent to a hard short. Some of those can be a PITA to trace down but depending on what you got, we'll see what we can do. There are a few guys here that are pretty good at tracing that down....

In case someone has a diagram you may want to also post the engine size.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 16, 2010, 8:11 PM

Post #3 of 12 (3358 views)
Re: Dash Lights Problem Sign In

Oh come on Sidom! Kitty is harmless little thing..........



Just don't come home with the wrong "Kitty" food and she's fine,

T



Sidom
Veteran / Moderator
Sidom profile image

Aug 16, 2010, 9:27 PM

Post #4 of 12 (3354 views)
Re: Dash Lights Problem Sign In

Sly Sly


RyanV
User

Aug 16, 2010, 9:52 PM

Post #5 of 12 (3349 views)
Re: Dash Lights Problem Sign In

Okay, so the engine is a 1.3 liter Suzuki, 4 cyl., even though the car is a Geo Metro. I think the Geo Metro was based off of a Suzuki car or something like that. Anyway, when I turn the dimmer adjuster knob, the check engine light for instance does not change. There aren't a lot of other lights. I have to get a bulb for the dome light to see if it even works.

The wire connector that goes to the dimmer adjuster knob has three wires going to it.

Cheers,
Ryan


Sidom
Veteran / Moderator
Sidom profile image

Aug 18, 2010, 9:22 PM

Post #6 of 12 (3329 views)
Re: Dash Lights Problem Sign In

Ok.....We'll start backwards on this. Your switch has 3 wires, 2 are power & one ground. 1st thing to do is verify power on both connecters and make sure the ground is good. If that is the case the switch is bad. By the diagram you can see there is multiple legs going into the switch. If all lights work except the dash. The you will need to trace down the dash leg. If none of the wires have power. Then you have to go back to the gang connection (I can post the other diagram) or where the power comes out of the distribution center. Before you get to deep there is a light relay I would check before tearing things up.....

Grab your voltmeter or test light & have fun....




RyanV
User

Aug 22, 2010, 9:29 PM

Post #7 of 12 (3307 views)
Re: Dash Lights Problem Sign In

Okay. So I was trying to test the relays, but didn't really know how to test them. I tested the wires that they plug into in the engine compartment, and those tested good, they lit up the test bulb.

Also, I have had a turn signal problem at the same time, so I was trying to figure that out as well, and now I think they may be related. I had tried to test the turn signal socket with the bulb tester, and it didn't work before, but when I unscrewed the plastic case (which is broken) and let the wiring hang out, then it did light up the tester. So what I think I discovered is that because the case is broken it was holding the turn signal bulb socket at an angle, and it made a short, or grounded out on some metal. So I disconnected the turn signal socket, and I am going to get a new one with the plastic case at a junkyard.

However, I was hoping that after I disconnected the turn signal bulb socket that the dash lights would work (thinking they might be connected), but still nothing. But, I did check the wires that go to the dimmer adjuster again, and now they work and they light up the test bulb (presumably they work because I got rid of the short in the turn signal bulb socket?).

So, could the short have burnt out the dimmer switch or a relay somewhere? And, how would I test these? It seems that the wiring is good as far as I can tell.

Cheers


Sidom
Veteran / Moderator
Sidom profile image

Aug 22, 2010, 10:52 PM

Post #8 of 12 (3305 views)
Re: Dash Lights Problem Sign In

Ground the red/green wire (not the red/yellow) and see if the dash lights come on. If the do you either have a bad dimmer switch or ground. To check the ground hook your test light on the pos batt term & probe the ground wire (black), the test light should light up if the ground is good......

When you say "they", I'm assuming both the red/green & red/yellow wires have power.....


RyanV
User

Aug 23, 2010, 10:21 PM

Post #9 of 12 (3289 views)
Re: Dash Lights Problem Sign In

okay, so I think I tested them the way you explained. I clamped one end of the test light to some metal, and I used the pointer to touch the wire connector that goes into the dimmer switch. I put it in both the power wires, and the bulb lit up with both, but the dash lights did not come on (I did this at night to make sure I could see them if they came on - i also made sure the car was running and the headlights were turned on). I haven't checked the ground yet, as I am not sure which ground wire it would be.

Please let me know if I did the test wrong, and if not, let me know what you think the problem could be. I appreciate your help.
Cheers


Sidom
Veteran / Moderator
Sidom profile image

Aug 24, 2010, 8:15 PM

Post #10 of 12 (3266 views)
Re: Dash Lights Problem Sign In

Well you did pretty good but missed a couple of points.....

Real quick & I try to keep it short so it doesn't get confusing. There are 2 types of basic circuits. Series & parallel. Series is hooked together all the way down the line. It's like the old Xmas lights, one goes out & they all go out. Parallel shares a common power & ground but has it's own leg so if one leg goes out the rest of the circuit isn't affect & keeps working..

About 98% of all automotive circuits are parallel. This one here is a perfect example of a parallel circuit. Each leg of this circuit has one load on it. Think of a load as a pig that eats 100% of the power for that circuit. When the circuit is working properly, the load uses all the voltage and there is no voltage on the ground side. When you have an open circuit the load turns into a switch and passes the voltage on thru, using none of. In an open circuit you will be able to measure voltage right down to the open spot, WHEREEVER it is....

Ok knowing this, test the circuit again. Look at the wiring diagram. You will see 5 or 6 loads (I'm to lazy to scroll up) going into the dimmer. They all come together at on point & go into the dimmer..

The 1st test is, do all the legs work, some of them or none of them? Read the schematic and see all the different lights on that circuit. With the dimmer hooked back up, turn on the lights (we already know the dash lights don't work). Do any of lights on that circuit work & can be controlled with the dimmer? If they do, then that sux cuz it means the circuit, the dimmer & ground are good and you have a bad leg for the dash lights. That circuit will have to be isolated & tested.....A total PITA.

If none work, then that's good, you have already verified power on both wires but still need to check the ground. Take that end you put on bare metal & attach it to the battery positive. Then touch a bunch of ground stuff, engine block, fender, anything metal. Each time the light should light up. Now touch the ground wire for the dimmer switch. It should also light up. If it doesn't then you have a bad ground. If it does then it's really looks like you have a bad dimmer switch. But just to be sure there is one more test......

This is the part some guys have trouble with, running a wire with 12v on it, directly to ground, you can't use a test light because that won't ground the circuit. You now know if there there is load up stream with an open circuit the ground wire will measure 12v and that is what you are getting, so grounding that wire will just complete the circuit.
Now this is very important you ground the correct wire. The power wires have different color tracers to identify them, I can't see the diagram right now but believe it was a red w/yellow tracer for the lights. I don't remember the power source for the dimmer...... Ground the power coming from the lights directly and all the lights should come on.... If by chance you ground the power source wire for the dimmer switch ( which has no upstream load, the dimmer is the load) then your new name is going to be Sparky or Smokey because you will fry something......

If you aren't totally sure, then don't ground the wire (this is where a power probe comes in handy).

So in a nutshell....

1st hook the switch back up and see if ANY of the lights work.

2nd test the ground with a test light off the pos bat term

3rd ground the light circuit in front of the dimmer to see if the lights come on (ONLY IF 100% POSITIVE OF CORRECT WIRE)

UPDATE......

Red/green is the wire coming from the lights
Red/yellow is the power source for the dimmer-----DO NOT GROUND THIS WIRE........


(This post was edited by Sidom on Aug 24, 2010, 8:18 PM)


RyanV
User

Oct 3, 2010, 9:16 PM

Post #11 of 12 (3164 views)
Re: Dash Lights Problem Sign In

Thanks a lot for your help. I did the two easier tests and discovered that everything was fine, so I am assuming it is probably the dimmer adjuster switch. I looked into buying one, but it was too expensive, so I am just going to get a small battery powered light to put in the dash for now.

Thanks again,
Ryan


Sidom
Veteran / Moderator
Sidom profile image

Oct 3, 2010, 9:44 PM

Post #12 of 12 (3162 views)
Re: Dash Lights Problem Sign In

If you ground the red/green wire going into the dimmer switch, do the dash lights come on?

If so and is was mine, I would be tempted to run that wire to ground with a toggle switch in line. It would be full bright with no dimmer control but you could always switch if off if need be.....


(This post was edited by Sidom on Oct 3, 2010, 9:44 PM)






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