Dashboard lights - "software" or switch problem?
Thread Starter
Heel & Toe
Joined: Jun 2004
Posts: 17
Likes: 0
From: Wilmington NC
Dashboard lights - "software" or switch problem?
This forum has saved me before...I'm asking for help yet again [searched previous posts, didn't see anything on this specific problem]. All the dashboard lights (instruments, radio, etc) in my '99 no longer illuminate when I switch the headlights on. However, I know the lights themselves work fine, because when I shut the car off and open the door, they all illuminate- I just can't get them to come on when I'm driving (tried flicking the headlights on and off, etc)! I assume there is some sort of switch, relay, or software that is making the car "think" that the lights should not be on. Help would be very much appreciated, before I take it into the dealer for $troubleshooting$.
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
Don't mean to sound dumb, but is the dimmer control (round **** left of the cluster) turned up? I asked the simple things first. I used to work for IBM. The first thing I asked when I talked to the customer was "is it plugged in?" The second thing was "are you sure it's plugged in?" 
I don't know exactly how the C5 dash lights work but from watching the data buss I do know that the dimmer info is on the buss so I assume the lights are controlled by serial data. If none of your lights work, radio, AC controls, or cluster then I would start by checking the dimmer control. It is the round **** left of the cluster, same as the HUD control if you have a HUD, same one the controls the dome lights when turned past the click. You have to remove the cluster to remove the dimmer control.
Good luck
I don't know exactly how the C5 dash lights work but from watching the data buss I do know that the dimmer info is on the buss so I assume the lights are controlled by serial data. If none of your lights work, radio, AC controls, or cluster then I would start by checking the dimmer control. It is the round **** left of the cluster, same as the HUD control if you have a HUD, same one the controls the dome lights when turned past the click. You have to remove the cluster to remove the dimmer control.
Good luck
Thread Starter
Heel & Toe
Joined: Jun 2004
Posts: 17
Likes: 0
From: Wilmington NC
Simple things are always good, I usually forget them...but in this case I actually did try that- unfortunately the dimmer control has no effect (I don't have the HUD). The lights are full bright when I open the door after the car is shut off, but completely off when I'm driving, regardless of dimmer **** position. Thanks.
Melting Slicks
Joined: Jan 2003
Posts: 3,251
Likes: 4
If it's only the dash lights then is probably going to be the relay located behind the central vent. However if it includes loss of tail lights(not brake lights), loss of fog lights and directionals, then it's the multi-switch stalk on the left. $130 from GMpartsdirect.com or $260 at the dealer. It took me 1 hour to R&R the part.
Thread Starter
Heel & Toe
Joined: Jun 2004
Posts: 17
Likes: 0
From: Wilmington NC
Directionals work ok, but my cruise control was intermittent and is now dead, and dealer said it was the multi-switch stalk (which I opted not to replace at the time); I didn't realize that part could cause loss of the dash lights.
Thanks,
Mike
Thanks,
Mike
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
I'm sure the multi-switch stalk is the source of the dash light signal but I would think it would be the same signal as the marker lights. So if your outside marker lights still work then I would think the switch is not the problem. And since they do come on when you open the door it don't seem like it would be a relay. I will look this up in the manual tonight to see how the system works. 99 Coupe, right?
Can anyone verify if the dimmer has any control of the dash lights when you just open the door without the lights on? I would but I don't have doors!
Can anyone verify if the dimmer has any control of the dash lights when you just open the door without the lights on? I would but I don't have doors!
Melting Slicks
Joined: Jan 2003
Posts: 3,251
Likes: 4
Originally Posted by SpeedyZ
Can anyone verify if the dimmer has any control of the dash lights when you just open the door without the lights on? I would but I don't have doors!
I believe I still have the diagrams for the R&R if you need them I can email it to you later.
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Thread Starter
Heel & Toe
Joined: Jun 2004
Posts: 17
Likes: 0
From: Wilmington NC
muchos thanks guys
Originally Posted by SPEEDYZ
I'm sure the multi-switch stalk is the source of the dash light signal...I will look this up in the manual tonight to see how the system works. 99 Coupe, right?
Originally Posted by SPEEDYZ
Can anyone verify if the dimmer has any control of the dash lights when you just open the door without the lights on? I would but I don't have doors!
Originally Posted by IM QUIKR
The dash lights will come on full with the door open and are separte from the dimmer switch. Mine did the same thing. My scenario began with the loss of the dash lights intermitently and progressed to the loss of what I listed above. It seems to be a common fault and I would say with 99% certainty that the switch is dying.
I believe I still have the diagrams for the R&R if you need them I can email it to you later.
I believe I still have the diagrams for the R&R if you need them I can email it to you later.
Sounds to me like I need to replace the stalk and I'll have lights and cruise control back. I lost the damn dimmer **** when I was playing with this weeks ago, so I need to order parts anyway...I'll just add the stalk to that. $130 is great, I think a dealer or repair shop quoted me $400 to replace the stalk months ago when I asked about fixing the cruise control.
If you could email the diagrams to me at mike7562@earthlink.net, that would awesome. I am not much of a home mechanic, but the few things I've done myself I've finished saying, "that actually was pretty easy". If you can do it in an hour, I should be able to do it in 3-4 hrs
.
Originally Posted by IM QUIKR
It's an easy fix but you'll need torx (short and long)tools at about $11 from Sears.
Thanks again guys!
Semper Fi,
Mike
Melting Slicks
Joined: Jan 2003
Posts: 3,251
Likes: 4
check your email.
If you look at your steering column, you'll see it's tough to get a long tool in where you need to and visa versa. the covers need long tools. I think I used allen wrenches and the torx under the covers needed shorter tools. No big deal, you'll see what I mean when you open her up.
If you look at your steering column, you'll see it's tough to get a long tool in where you need to and visa versa. the covers need long tools. I think I used allen wrenches and the torx under the covers needed shorter tools. No big deal, you'll see what I mean when you open her up.
Last edited by IM QUIKR; Aug 5, 2005 at 05:26 PM.
