Dome light problems....

[Nitro187]

Ok, here is the thing.

I have a 96 grandam GT, and my dome light USED to work, but now it doesn't.

When I open my doors ( or turn the switch on ) the lights under my dash board turn on just fine, and go off like they should ( just like the dome light should too) but the dome lights (two lights in the front, and two in the back, one by each door) don't come on.

I thought the light bulbs were dead (all four? but ok) so I manually pressed the switch that is there, and they turn on just fine!

Any ideas on what I can do to get these to work? Is there a known issue with a wire maybe, that sends a signal to those 4 lights to tell them to turn on?

Please help, thanks!

[e2helper]

Hi,
Good description!

Yes, at least you know that the module controlling lamps is working (since your footwell lamps work). Also since the lamps in roof operate in the "map" mode you know they have power. The problem then must be that the wire that grounds these lamps is open circuit somewhere. I don't a schematic to look at but there is likely a single circuit going from the instrument panel wiring to the headliner wiring that isn't working on your vehicle.

[Nitro187]

Thanks for the reply, Hmmm.. I have the schematic:

http://www.nitrolic.com/b.jpg

Where do you think the break is? keep in mind, all four lights on the roof do not work with the control switch by the steering wheel, or the automatic light... they only work when you press the buttons beside them. :\

Thanks!!!

[e2helper]

Sorry for delay - there are new forums to me.

The problem is going to be the white wire running from the splice just above the rear door jamb switches over to the splice under all the header/quarter courtesy lamps. Having that wire broken would cause your complaints.

However the manual you have is not GM service manual and it is not showing some of the detail on how the wire gets from point to point.

There is also some inaccuracies about how the power feeds to the lamps work but that isn't too critical since your problem is the "ground" side of the lamps.

Good luck. If you could find actual GM service manual for your model I would be able to be more specific. I will see if I can find more info somewhere as well.

[Nitro187]

Yeah, I even looked on ebay, and couldn't find an actual GM service manual.

So you say a white wire that goes from the rear door jam switch, to the courtesy lamps is the problem? hmmmm..

So basically, if I just look at all the wires going to the roof of my car, find a white one, test it, that should be the prob?

[e2helper]

Well there is really no problem with getting an acutal GM Service Manual, it is just that they are d*mn expensive ($120 in your case)

http://www.helminc.com/helm/Result.a...M0SPA50R6XBPP6

However a bit of good news........

I think the 1998 model is close enough to your vehicle to help in diagnosis so check out this link.

http://www.geocities.com/raj380/mali...ntlighting.zip

If you have a pretty decent connection I could have included a file with lots of graphics but it was around 2 meg and 25 pages.

Anyways this information gives enough information to diagnose your vehicle correctly. After reviewing it post again.

Don't ask me how I get this stuff

[Nitro187]

Hey, thanks for the pics. I have a really good connection, send me as much as you can

So what should I be looking for in these pics?

[e2helper]

OK,

Here you go
http://www.geocities.com/raj380/mali...onentviews.pdf

Sorry about all the different file types - and hope you can view TIFs

I would have put all in 1 PDF file but have an application that doesn't play with Abode Acrobat very well on this puter.

Anyways ----

Look at file lefthandip.pdf to see location of inline connector C202 which is between the body and headliner harness (headliner runs up driver A-Pillar). THIS IS WHERE TO FIND THIS WHITE WIRE OF INTEREST.

Now look at courtesypwr.tif (it is pretty busy) but look for the triangle with "A" symbol. This is this white wire in the body harness - don't do anything here, it just shows you how your vehicle's interior lighting REALLY works - not like the drawing you showed originally -- sorry.

Now look at file courtesygnd.tif. Find the corresponding "A" symbol. This is how this wire gets to this page. See the C202? Cavity E of this connector has the white wire. So it would be really interesting if you could somehow check if this wire at this connection was grounded when your doors were open and your footwell courtesy lamps were on - got a test light?? If it is grounded then your problem is in the headliner. If it isn't grounded then the problem is in this wire and you have to go back to previous page to track it down.

Sorry if I am overwhelming you with details. If you can't tell I do this stuff for a living (LOL).

[Nitro187]

awww... geoshities won't let me download.

could you e-mail it to me? [email protected]

Thanks, I hope it's not a problem.

[e2helper]

Yes - I agree, when I tried to download as a test it crashed my computer. Actually for this particular issue that info is overkill but I will e:mail it to you anyways because might be of use in the future

Oh I forgot to mention there is one additional test you should try before trying to access this connector C202 - if your vehicle has factory keyless entry.

Well if it does, when you do an UNLOCK with key fob what lights in the vehicle turn on (same footwell or headliner or neither)? Because this module is located in the rear of vehicle it actually tests out some other portions of wiring in the vehicle.

Anyways good luck and let me know how things turn out. The next thing you might be wanting to know is where the wiring splices are located.

EDIT - The original link started working for me again. Must have gotten locked out when it crashed my computer the first time.

[Nitro187]

I think i'm totally lost.

[e2helper]

Haha, I do have that effect (sorry)

Ok lets start -

1. Does your vehicle have a factory keyless entry sytem (key fobs) and if it does what interior lamps (if any) turn on when you UNLOCK doors?

2. What type of device do you have that would allow you to check for voltage? Voltmeter, test light, ??

[Nitro187]

1. Yes, it has factory keyless entry, no lights turn on though. :\ I just tested last night (from what I gathered from your previous post.)

2. I do lots of electronics, I have lots of voltage readers. I just don't follow your instructions, probably cause this has been a VERY long week. hahahah.

Do you have msn messenger or ICQ? we could speak through there. :P It may be easier... then we can post the results here on the board after. Let me know.

[e2helper]

Yes I do have MSN
Based on your results with remote keyless (that the footwell lights didn't turn on) and the more detailed information we have on your vehicle's wiring I would have to suspect that Splice S321 but I am thinking there are a couple other things you could try to help confirm this using a jumper wire at the harness inlines. I'll keep a look for you on MSN