Dome lights will not shut off

The dome lights will not shut off. The door and deck switches are working. The lights will shut off once in a while but most of the time they stay on. I have gone so far as to unplug all the switches and they still stay on. Could some one please give me a hint as to what to look for.

Welcome into the CF forums!
 
Not sure which lights you're referrin' to there, Paul... How 'bout the radio? Does it stay on when you get out of the vehicle and lockdown for the night?

All the interior lights the door lights the lights in the pillars behind the seats the lights under the dash. I will try the radio but I don't think it will shut off either. There are occasions that the lights fade out and shut off.

quote:

ORIGINAL: Paul Spickard

All the interior lights the door lights the lights in the pillars behind the seats the lights under the dash. I will try the radio but I don't think it will shut off either. There are occasions that the lights fade out and shut off.

 
AHA!
 
This sounds like a timer fault in the computer... When you turn the motor off, interior lights come on, and accessories stay powered up, including the radio, until you pull the door handle. Or until 8 - 10 minutes have passed.
 
Not sure of your solution, but this might be the direction to go... 

Next time you shut down, and the accessories don't cut off, pull the passenger door handle to open it. See what happens

The radio shuts off when either door is opened but the lights stay on. Looking at the form for the C4's this same problem has been noted a couple of other times. In reviewing that, it was stated that problem was a printed curcit board a relay or a body computer. I've found the printed curcit board and had it checked out by the electronics department at work it is fine. (its just 3 diodes) I have yet for anyone to be able to tell me were the relay is. Or for that matter were the body computer resides. The car is a 93 by the way.

quote:

ORIGINAL: Paul Spickard

If you have a interior bulb missing it will flash sys on the dash.

Paul, if you pulled the bulb while working on the lights-staying-on problem in your thread, you might be onto the problem there. That is, IF 'sys' can mean things other than low system voltage.

Betcha!?


The sys flashes on the dash if the bulbs are removed. I did this to keep the battery from going dead. If I replace the bulbs the sys goes away but the lights stay on most of the time. It seems to me that anything that changes the exceptable resistance in the interior curcit sets off the "sys" signal. That would explain why low voltage a change in the sound system or removing a light bulb would cause this condition. I would like to eliminate the ground causing this problem. Could someone steer me to were the grounding points are located.

What year model is your car?

I'm assuming yours is a 93 from another post. Here is a wiring diagram for a 93 interior coupe. I suspect your problem is in the central timer module, but without a Tech 2 scanner to check it ,

Having file upload problems. As soon as it works will upload it again.

Thanks I'll see what I can do.

the car is a 93
Thanks we'll see if this gets me anywhere. Were on the car can I find the ccm?

quote:

ORIGINAL: mech259

I'm assuming yours is a 93 from another post. Here is a wiring diagram for a 93 interior coupe. I suspect your problem is in the central timer module, but without a Tech 2 scanner to check it ,

Hey mech... The timer module is what I was gettin' at when I asked him if the radio cuts off when he opens the door, and also if the timer's ground/interrupt in the driver's door might be bad. He said the radio DOES cut off when either door is opened.

You still think it could be the timer module? Is the timer module's clock integral with the computer, or is it a dedicated clock itself?

quote:

ORIGINAL: mech259

I'm assuming yours is a 93 from another post. Here is a wiring diagram for a 93 interior coupe. I suspect your problem is in the central timer module, but without a Tech 2 scanner to check it ,

 
Thanks Mech
 
Big help as always

Where are the (timer module?) and the ccm located? Also am I to assume correctly that the central control modlue is the same as the body control computer on this vechile. Looking at the diagram the only things controlling interior lights are one switches, two a diode module, and three a ccm. The diodes are fine the switches are fine so I'm guessing the ccm is not. Or is the ccm controled by a body control computer, timer module some other relay or switch that is not on this diagram.

quote:

ORIGINAL: Paul Spickard

the car is a 93
Thanks we'll see if this gets me anywhere. Were on the car can I find the ccm?

 
I'll have to get back to you on that, more than likely it is behind the passenger side dash. In your e-mail, you mentioned rear deck lights. I would suspect the deck switch assembly.

In later years, GM turned those functions over to the BCM (Body Control Module), but I think the CTM controls lights and radio functions.

Well guys I thank all of you. It seems for now the problem is solved. I think th problem was in the dimmer switch on the the dash. I've replaced it and everything seems to be fine. Feel kinda foolish to be honest .

Hey Paul.
 
I am having the exact same problem with my 1990 C4.  So the dimmer switch was your problem, a?  How tough was it to replace Paul?  Please advise.  Thanks!

simple solution (and general good idea for storage, and anti theft) is install an easy to get to but hidden kill switch.  Now, this cures the symptom, not the problem, but they can come in handy when you are traveling as well.  (hotel parking lots anyone?)