Car Question 2003 Monte dash lights

[scottb]

2003 monte carlo LS, instrument panel lights not illuminating. The headlights function, all exterior bulbs working. Turning the headlight knob to ajdust the brightness of the lights does not change or cause a flicker with the brightness of dashbulbs.

The IP section that displays the PRND123 is only partialy visable and is about 25% as bright as normal.

I looked in the owners manual and that lists only 2 fuses that have anything to do with the IP lights. Both of these fuses were in the fusebox on the passenger side of the dashboard. One fuse listed as IP and front side marker lights, ( front side marker lights function) and the second fuse listed IP / interior footwell. Interior footwell and overhead lights function.

I know the owners manual is not the same a service manual, but is a place to start. All fuses, on both sides of the dash board and under the hood checked good.

A weird thing that may or may not be related. If the climate control fan is in the dash vent postiton, press the button for external air instead of recycled air, and have the AC button on, pushing in the rear defroster button turns off the indicator lights for the external air and the AC buttons. So maybe there is an issue with body control module?

I should be able to get a wiring diagram either on line or tomarrow from the library. I am not sure if it some thing as basic as the headlight switch since the brightness used to be adjustable, or if the body control module is somehow in the circuit.

Any thoughts?

Edited February 14, 2011 by scottb

[hue jass]

What was the last thing - if anything - you did to the car?

Could be a headlight switch.

[scottb]

Nothing electrical done to the car. Not being a smarty pants, but i changed the oil in December and 3 weeks ago I washed the car. Dashlights functioned properly Friday night. Did not drive the car Saturday. Just drove the car Sunday night prior to posting, so like 6 PM.

The only item i normal use electrically would be a charger for cell phone or GPS. The power cig/lighter plug still functions.

[chevysoldier]

Not being a smart ass, but did you verify the bulbs aren't burned out? I've see dashes where a bulb will burn out and the customer doesn't notice then later another burns out and is completely dark. You'd think since all were out it'd be a wiring issue or fuse but always start simple.

[scottb]

I see the logic, but all lights were functioning friday, last time i drove the car. I would have also noticed if the radio light was not working, cuz i tend to always listen to the radio. Plus too, the gear indicator has always functioned, the PRND123

The only bulb that was not functional prior to today was the driver side temp light for the "hot /cold" was not working. I never replaced that one because I never looked to see what type of bulb that takes.

[ReconRat]

If it's not a fuse, then the circuit is open. Stalk switches are notorious for failure. I'd jump right to the steering column connector and check the variable resistance across the circuit for the stalk switch for the instrument panel lights. Yeah, you'll need an accurate wiring diagram. Other than that, I'd think of checking the instrument panel ground, since all are out. I'd hate to think that a simple light circuit ran through a control module. That would be a pain.

Edited February 14, 2011 by ReconRat

[scottb]

I got out of the car repair field about 1994 prior to more control modules in vehicles. My last vehicle i worked on with a headlight issue was my 1984 Chevy plow truck, that was a super basic circuit. I did see a few mentions on the internet about failed headlight switches. I would like to confirm the headlight switch before just throwing money/parts at it. Once I get the wiring diagram, i should be able to tell what output from the switch controls the brightness of the dash/radio lights.

[chevysoldier]

Yeah, sounds like a wiring or BCM issue.Get some schematics and start tracing.

OR you have a gnome hiding under your dash.

[scottb]

To rule out the Gnome, I'll look for a Juliet to flush him out.

[jporter12]

I'll look at a diagram tomorrow and see what it could be. Just off the top of my head, the headlight switch is usually a likely candidate, but I'll have to look over the system.

Edit: Make that later today, actually.

[DoughnuT]

There is still the possibility that they are burned out. I would check the wiring and such like everyone else has stated, and find out what bulbs the replacements are. With the gear indicator still lit up, even though it is dimmer than normal, I would almost bet on the bulbs being burnt.

If it was the switch, then the gear indicator wouldn't light up correct? That light should be on the same circuit as the rest. Not to mention no lights should come on, since all the lights are ran through one switch, if it is bad. That has been my experience any ways.

I just went through changing the bulbs in my ranger, because one went out in the speedo, and others were dim. Only took about 30 minutes for the first time to do it. Had to take the cluster out of the dash, but that was only 10 bolts maybe.

All my experience is with Ford, so I can't tell you for sure that Chevrolet is the same. Look into everything, to rule out all possibility of something major.

[scottb]

Thanks for all the replies. Once I get the wiring diagram, i will focus on the headlight switch. Making sure to check voltage from the switch to the cluster. That answer will determine my plan of attack.

Probably too, just for a baseline, i should check the charging system just to make sure i do not have an over charge condition and other electrical or bulbs might fail.

[scottb]

I moved the car this morning and turned on the headlights. Not sure why i did this, but with the headlights on, i lifted up slightly on the heaglight knob, and the dash light illiminated. so that tells me there is an issue with the switch itself.

I'll price out on of those this morning. If I call the dealer and auto part stores and they have like 50 in stock, that tells me this is a commonly replaced part.

[jporter12]

There is still the possibility that they are burned out. I would check the wiring and such like everyone else has stated, and find out what bulbs the replacements are. With the gear indicator still lit up, even though it is dimmer than normal, I would almost bet on the bulbs being burnt.

If it was the switch, then the gear indicator wouldn't light up correct? That light should be on the same circuit as the rest. Not to mention no lights should come on, since all the lights are ran through one switch, if it is bad. That has been my experience any ways.

I just went through changing the bulbs in my ranger, because one went out in the speedo, and others were dim. Only took about 30 minutes for the first time to do it. Had to take the cluster out of the dash, but that was only 10 bolts maybe.

All my experience is with Ford, so I can't tell you for sure that Chevrolet is the same. Look into everything, to rule out all possibility of something major.

The indicator is probably lighted through a different circuit. I'll pull the diagrams later this morning. We're getting ready to head out the door to take the kid to an appointment at Children's.

[scottb]

thanks porter